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Phase-based Alpha (α) Plane Relaying (APR) scheme has numerous advantages over the Current Differential Relay (CDR) for transmission line protection. Since the large Restraining Region (RR) in the APR makes high security against CT saturation, channel delay, line charging current and synchronization error. However, the APR loses its sensitivity for high resistance ground faults, especially single line to ground faults under outfeed conditions. Also, losing its dependability under close-in low resistance three-phase faults. Thereby, the sequence-based APR provides enhanced sensitivity with the cost of computational burden and complexity. Hence, in this paper, the concept of the average value (IAvg) of both end instantaneous currents is used as an auxiliary logic. In which, the polarity of IAvg is incorporated as an add-on logic to the conventional APR to confirm high resistance internal faults. Thereby, the requirement of sequence components can be avoided (negative and zero). To validate the proposed auxiliary logic, it is tested for the WSCC (Western System Coordinating Council) 9-bus, 110 kV, 50 Hz. System. The simulated results under various fault cases found authenticated results. In addition, the comparative assessment and validation with real-world data reveal the enhanced sensitivity of the proposed logic under high-resistance ground faults. [ABSTRACT FROM AUTHOR]

Low-voltage distribution lines lack efficient monitoring. With the massive proliferation of distributed energy resource supply, it is necessary to establish an effective monitoring system for low-voltage distribution lines to ensure the electrical safety and continuity of power supply services. This paper proposes monitoring system for low-voltage distribution lines based on the Internet of things (IoT) technology. An IoT based monitoring system contains a large number of low-voltage monitoring terminals, different manufacturers, and different types of terminal equipment to solve the interconnection problem of information interaction. This paper first analyzes the terminal functional communication requirements based on IEC 61850 standards. Further, the information models required by the electrical volume collection and non-electric quantity collection functions are studied. The information modeling for different types of monitoring terminal equipment is presented and thus provide the configuration suggestions. The monitoring terminal based on the information model developed in this paper is applied in a university campus to realize the monitoring of low-voltage lines and distributed power supply. [ABSTRACT FROM AUTHOR]

With the rapid development of social economy, the demand for electric power engineering is gradually increasing. The power supply system is constantly developing in the direction of large space and automation, and various high and new technologies are also constantly improving. The power monitoring data access control system is used to monitor and control the power production and supply process and improve the power supply efficiency. The further development of the region also has a higher demand for power and energy supply. For the problem that the natural environment of transmission and distribution lines in various power grids is uncertain, which makes the line operation unsafe. This paper proposed a power monitoring data access control system based on BP (back propagation, abbreviated as BP) neural network. This paper described the related concepts of BP neural network and power monitoring system, and described the functions and construction methods of power monitoring data access control system. On this basis, relevant experiments were carried out to verify the performance of the proposed system. The experimental results showed that the fault detection accuracy of the traditional algorithm was about 93 %, while the fault detection accuracy of the algorithm in this paper was more than 98 %. The highest accuracy rate was 99.88 %, and the accuracy rate of fault detection was greatly improved. [ABSTRACT FROM AUTHOR]

In recent years, with the development of smart grids, people have increasingly high requirements for the safety, stability, and reliability of smart grid operation. In actual operation, smart grids require real-time monitoring and control, while for low-voltage power lines, power line carrier communication is required for data transmission. However, in practical applications on site, the low-voltage power line environment is complex, with ground faults, electrical equipment interference, and other situations that can affect communication quality and reliability, leading to a decrease in the effectiveness of real-time monitoring and control. The research in this paper is based on a complex low voltage platform simulation platform to restore the on-site complex substation communication environment. The purpose is to improve the efficiency of automatic meter reading systems by using various communication methods in low-voltage substations, such as wireless public network point-to-point data transmission, optical fiber communication data transmission, power line carrier data transmission, etc. Automatic meter reading systems are an important means of low voltage substation communication. This article experimentally tested the maximum personnel allocation for meter reading using low voltage carrier communication technology, which was 8 people smaller than the maximum personnel allocation for traditional meter reading, and the minimum personnel allocation was 8 people smaller than the traditional meter reading personnel allocation. The electricity accuracy of meter reading using low voltage carrier communication was up to 96 %, while the electricity accuracy of traditional meter reading was 70 %. The maximum accuracy of line loss statistics for low voltage carrier communication technology meter reading was 90 %, while the maximum accuracy of line loss statistics for traditional meter reading was 68 %. The frequency of load anomalies found in low-voltage carrier communication meter readings within a month ranged from 30 to 60 times, while the traditional meter readings concentrated on 10–25 times. From these data, it is clear that communication meter reading in low-voltage station areas has advantages over traditional meter reading. [ABSTRACT FROM AUTHOR]

With the rapid development of the power system, the complexity of power system continues to increase. The large-scale of clean energy increases the complexity of the power system structure, which makes the power system's operating status complex and changeable. To ensure the safety, stability, and economic operation of the power system, the power system needs to maintain a certain spinning reserve capacity and ensure that the reserve is available. The spinning reserve optimization method based on fixed partitions cannot effectively deal with the source-net-load volatility and the line congestion problems caused by wind power. To this aim, this paper proposes a power system reserve capacity partitioning algorithm based on the spectral clustering algorithm considering wind power. First, the energy-reserve joint optimization unit commitment problem is built. Secondly, considering the uncertainty of wind power output and the line N − 1 failure, a risk assessment method for line congestion is established; then the power transfer distribution factor (PTDF) of the congested line is considered as the similarity measure. A method based on the iterative partition method based on spectral clustering is proposed. Finally, the reserve capacity configuration based on the dynamic partition results is determined. The IEEE-118 bus system is used in this paper to verify the proposed method. The results show that the reserve capacity dynamic partition method proposed in this paper determines the number of partitions automatically. Reserve capacity partitions are built reasonably. After the reserve capacity partitions, the availability of spinning reserve capacity is effectively guaranteed. [ABSTRACT FROM AUTHOR]

With the continuous development of society, power grid has become a major guarantee for social and economic development, and its coverage is also expanding. The power grid not only covers some developed areas, but also extends to remote mountainous areas with complex changes in geological and climatic conditions. However, at the same time, line failures and power outages caused by mountain fires are becoming increasingly frequent, which poses a significant threat to the safety and stable operation of the power system. Therefore, how to solve the problem of mountain fire on transmission lines has become an important topic today. The main purpose of this study is to achieve effective monitoring of transmission line mountain fires and provide more assurance for the stable operation of the power system. This article discussed the transmission line and traditional mountain fire prevention monitoring system, and combined the current hot machine vision algorithm to design the overall mountain fire prevention monitoring system, focusing on analyzing the differences between this system and traditional systems. Through experiments, it was found that the monitoring accuracy of the mountain fire prevention monitoring system designed in this article has been improved by 10.6 % compared to the traditional system at location 4, 7.6 % at location 6, and 7.9 % at location 7. At the same time, the real-time performance and anti-interference performance of this system were also better than traditional systems, and the overall performance of the system was better. Practice has proved that the system can effectively overcome the interference of external environment, and monitor and identify the fire situation in real time and accurately, ensuring the safety of transmission lines. At the same time, the research on machine vision algorithms in this paper can also help promote the more perfect development of power systems. Practice has proved that this system can effectively overcome the interference of the external environment, and continuously and accurately detect and identify the fire situation. [ABSTRACT FROM AUTHOR]

In some special geological areas, the inclination and displacement of transmission line towers are relatively common, which should be analyzed from various factors. Transmission towers are the support structure for overhead transmission lines and play a pivotal role in the safe operation of the power grid. Transmission lines are widely distributed. Transmission poles and towers are generally built in areas with poor geological conditions such as goaf, river bed and slope. Under severe weather conditions, the force on the tower may be affected to a certain extent, causing the tower to tilt, deform, or even collapse, and thus causing a wide range of power system failures, which have a great impact on people's production and life. Based on this objective problem, this paper has mainly studied the intelligent recognition methods and key technologies based on machine learning. In the experimental study of support vector machine (SVM) model based on machine learning, the average training time of genetic algorithm support vector regression (GA-SVR) was the longest, reaching 1.462 s. The average training duration of double chain quantum genetic algorithm-least squares support vector regression (DCQGA-LSSVR) was the shortest, with 0.156 s. The average pose error of double chain quantum genetic algorithm-support vector regression (DCQGA-SVR) was the smallest, only 0.136, while the average attitude error of genetic algorithm-least squares support vector regression (GA-LSSVR) was the highest, reaching 0.45. Therefore, it is of the great significance to analyze abnormal vibration of the transmission towers based on machine learning method. [ABSTRACT FROM AUTHOR]

This paper proposes the improvements in deviation settlement mechanism of Indian electricity grid system through demand response management (DRM) with the objective to minimize real-time under-injection/over-drawl or maximize real-time over-injection/under-drawl with respect to scheduled injection/drawl such that the deviation settlement charge (DSC) is minimum, subject to the network power flow equations, transmission line capability constraints, DRM constraints and bounds on variables. The mechanism to settle the unscheduled transactions, commonly named as deviation settlement mechanism (DSM), has been implemented to achieve grid frequency stability by imposing penalties and paying incentives, also known as DSC, for over- and under-drawls from the scheduled transactions. In this paper, the improvements in DSM have been solved as an optimization problem to minimize the DSC for a time period of 96 time-blocks (each of 15 min duration). The proposed improvement in DSM has been tested on modified IEEE 9-Bus system. It has been assumed that the generators installed at bus numbers 1, 2 and 3 are the central generating stations, which are monitored and controlled by the regional load dispatch center (RLDC). The simulation results are obtained (with varying percentages of shifting and different participating patterns of prosumers) for which the remarkable benefits of the proposed improvement in DSM (in terms of DSC minimization and improvement in the voltage profile and power flow) have been presented. [ABSTRACT FROM AUTHOR]

In view of sensitivity, selectivity, and operating speed of the relay, the current differential technique is an alternative against overcurrent and distance-based techniques for long transmission line protection. Moreover, this technique has limited performance due to Line Charging Capacitive Current (LCCC), Current Transformer (CT) saturation further, by using synchronized data, the effect of LCCC can be nullified. However, in case of synchronition is lost, the performance of the current differential is not reliable. Hence, in this paper, the Inverse of Difference of both end Current phasors (IDC) is applied to prevent maloperation due to channel delay and synchronization loss. The simulation experiments are conducted under various operating conditions on a 345 kV, 50 Hz, IEEE 39-bus network using PSCAD 4.5 and MATLAB (R2020a). Results reveal the enhanced security under CT saturation, LCCC and sensitivity under high resistance line to ground faults. [ABSTRACT FROM AUTHOR]

In the electrical power system, a few transmission lines play a crucial role in cascading failures propagation. Once it participates in the cascading failures propagation process, catastrophic power blackouts will inevitably occur. In this paper, the Electrical Transmission Line-Stochastic Approach for Link Structure Analysis method (ETL-SALSA method) is proposed, which combines the Internet thinking with the physical characteristics of power system. At the same time, important transmission lines are screened to prevent cascading failures of the power system. Additionally, considering the influence of hidden failures, the expanded adjacent matrix concept is proposed. Based on the expanded adjacent matrix, fault propagation relationship and topology structure are also taken into account in the ETL-SALSA method. In the calculation process of ETL-SALSA method, Markov probability transfer matrix of the Stochastic Approach for Link Structure Analysis algorithm (SALSA algorithm) of random method is adopted, so as to achieve higher computational efficiency. Simulations carried out on the IEEE 39-bus electrical power system and the IEEE 118-bus electrical power system show that the ETL-SALSA method can achieve high-accuracy to screen important transmission lines compared with graph theory method and cascading failure simulation method. Moreover, the screening speed of the ETL-SALSA method can be enhanced for several orders of magnitude compared with cascading failure simulation method. [ABSTRACT FROM AUTHOR]

This paper presents a new fault classification technique for Thyristor-Controlled Series-Compensated (TCSC) transmission lines using Support Vector Machine (SVM). The proposed technique is based on the utilization of post-fault magnitude of Rate-of-Change-of-Current (ROCC). Fault classification has been carried out by giving ROCC of three-phases and zero sequence current as inputs to SVM classifier. The performance of SVM as a binary-class, and multi-class classifier has been evaluated for the proposed feature. The validity of the suggested technique has been tested by modeling a TCSC based 400 kV, 300 km long transmission line using PSCAD/EMTDC software package. Based on the above model, a large number of diversified fault cases (41,220 cases) have been generated by varying fault and system parameters. The effect of window length, current transformer (CT) saturation, noise-signal, and sampling frequency have also been studied. It has been found that the proposed technique provides an accuracy of 99.98% for 37,620 test cases. Moreover, the performance of the suggested technique has also been found to be consistent upon evaluating in a 12-bus power system model consisting of a 365 kV, 60 Hz, 300 km long TCSC line. Comparative evaluation of the proposed SVM based technique with other recent techniques clearly indicates its superiority in terms of fault classification accuracy. [ABSTRACT FROM AUTHOR]

Intelligent threshold value improves the speed and accuracy of any fault detector unit. But in the literature, any such traditional threshold selection mechanism is not available to implant in the fault detector unit of protective relay. This paper introduces a swarm intelligence-based threshold setting mechanism for fault detector. In this context, the Euclidean distance approach (EDA) with a single detection index is used for transmission network protection. The detection index function is formulated with fault parameters on a priority base. Further, the modified particle swarm optimization technique with adaptive inertia strategy is used to identify the optimal threshold value of detection index function. With swarm intelligence based optimal threshold, numerous cases are investigated on a test power system and obtained results show the efficacy of the method. [ABSTRACT FROM AUTHOR]

Emerging technologies in an electric vehicle (EV) had greater advancement in the control, batteries and electric motors design. But safety and reliability are the major concerns when the consumer is dealing with a high voltage conductor for charging. The recurring of plugging in the switch for charging is an undeniable disadvantage. Therefore, to eliminate the human intervention in charging of a battery, wireless power transfer (WPT) will be the most effective methodology to charge the EV. This paper aims at building the prototype of 1 kW inductive WPT with high frequency supply with power converters. To design this system, standards of EV charging systems are incorporated; also, a suitable coil structure is identified for the given EV model as per the standards. The mismatch or misalignment of the receiver coil, air gap between receiver–transmitter (i.e., proximity) and compensation techniques are considered in this work. Efficient design of power electronic converter is implemented for both transmitter and receiver side. Both coil design model and the power electronic system are integrated to test the performance of proposed WPT technology. [ABSTRACT FROM AUTHOR]

Thyristor Controlled Series Capacitor (TCSC) is employed as actuator in an interconnected power system using Supplementary Damping Controller (SDC) to enhance the power transfer capabilities between areas as well as damp out the Inter-Area Low-Frequency (IALF) oscillations by varying the impedance of transmission lines. The time-varying delays in the feedback loop and asymmetric saturation limits at the output of TCSC may reduce the performance of the designed controller and lead to closed-loop instability if these are not considered in the process of controller design. Usually, a Minimum Absolute Saturation Bound technique (MASB) is used to convert asymmetric saturation limits into symmetric one. However, such consideration provides an apparent conservative and degrades the performance of the control system. To reduce the conservative in the control design process, a Normalized Saturation Bound (NSB) technique is used in this paper to convert asymmetric saturation limits of TCSC of time-delayed power system. The L-K functional and generalized sector conditions are utilized in the proposed controller design process to compensate the effect of time-varying delay and converted symmetric saturation limits. Sufficient conditions required for controller design are formulated in LMI form. 2-area 4-machine power model is used to verify the performance of the designed controller. From the simulation results, it is observed that the designed controller is giving superior performance in the present of time-varying delays and asymmetric saturation as compared to the designed controller using MASB technique. [ABSTRACT FROM AUTHOR]

In this paper, a simple and fast approach is suggested for fault detection in transmission lines. The proposed technique utilizes a modified cumulative sum approach for a modal current to identify faults. The modal current is derived by proper linear mixing of three-phase currents. Since different types of faults may occur in transmission lines, all three-phase currents should be considered during fault analysis. By converting three-phase currents to a modal current, the processing time is reduced and less memory is needed. In this paper, a modal current is processed instead of three-phase currents. The modified cumulative sum approach presented in this paper is capable of decreasing computational burdens on the digital relay and accelerating the fault detection procedure. The proposed fault detection technique is evaluated in four different systems. Moreover, some real recorded field data were deliberated in the efficiency assessment of the proposed method. The results denote high accuracy and quickness of the proposed approach. Furthermore, the performance of the proposed methodology is compared with some other similar methods from different aspects. [ABSTRACT FROM AUTHOR]

In the transmission line, the series compensation device is often used to improve the transmission capacity. However, when the fixed series capacitor (FSC) is used in high compensation series compensation device, the stability margin cannot meet the requirements. Therefore, thyristor controlled series compensator (TCSC) is often installed in transmission lines to improve the transmission capacity of the line and the stability of the system. For cost considerations, the hybrid compensation mode of FSC and TCSC is often adopted. However, when a single-phase grounding fault occurs in a transmission line with increased series compensation degree, the unreasonable distribution of FSC and TCSC will lead to the excessive amplitude of secondary arc current, which is not conducive to rapid arc extinguishing. To solve this problem, this paper is based on 1000 kV Changzhi-Nanyang-Jingmen UHV series compensation transmission system, using PSCAD simulation program to established UHV series compensation simulation model, The variation law of secondary arc current and recovery voltage during operation in fine tuning mode after adding TCSC to UHV transmission line is analyzed, and the effect of increasing series compensation degree on secondary arc current and recovery voltage characteristics is studied. And analyze the secondary arc current and recovery voltage when using different FSC and TCSC series compensation degree schemes, and get the most reasonable series compensation configuration scheme. The results show that TCSC compensation is more beneficial to arc extinguishing under the same series compensation. Compared with several series compensation schemes, it is found that with the increase of the proportion of TCSC, the amplitude of secondary arc current and recovery voltage vary greatly. Considering various factors, the scheme that is more conducive to accelerating arc extinguishing is chosen. [ABSTRACT FROM AUTHOR]

Traditionally, transmission lines have been operated based on static thermal rating, which is determined by fixed and conservative meteorological data. It causes underutilization of potential transmission capacity. To overcome this limitation, this paper presents seasonal time scale, which can provide flexible ratings. Seasonal meteorological parameters are uncertain. The uncertainty can directly impact the conductor temperature, and eventually impact transmission capacity of the lines. In order to account for the uncertainty, this paper presents an uncertainty analysis model. This model consists of three parts: establishment of probability distribution models, Monte Carlo simulation, and operation risk assessment. In the case study, the actual meteorological data for 7 years in the Weihai is utilized, and is divided into four subsets by spring, summer, autumn and winter. The uncertainty analysis model is tested on an actual 47 km Wei-Kun line and a 4-bus power system. Results show that potential transmission capacity can be extracted if seasonal meteorological parameters are taken into account. [ABSTRACT FROM AUTHOR]

This paper presents a phasor-distance based faulty phase detection and fault classification technique for parallel transmission lines. Detection and classification of faulty phase(s) have been carried out by deriving indices from the change in phasor values of current with a distance of one cycle. The derived indices have zero values during normal operating conditions whereas the index corresponding to the faulty phase exceeds the pre-defined threshold in case of occurrence of a fault. A separate ground detection algorithm has been utilized for the identification of involvement of ground in a faulty situation. The performance of the proposed technique has been evaluated for intra-circuit, inter-circuit and simultaneous faults with wide variations in system and fault conditions. The suggested technique has been evaluated for over 23,000 diversified simulated fault cases as well as 14 recorded real fault events. The performance of the proposed technique remains consistent under Current Transformer (CT) saturation as well as different amount and direction of power flow. Moreover, suitability to different power system network has also been studied. Also, faults having fault current less than pre-fault conditions have been detected accurately. The results obtained suggest that it is able to detect faulty phases as well as classify faults within quarter-cycle from the inception of fault with impeccable accuracy. Besides, as modern digital relays have been already equipped with phasor computation facility, phasor-based technique can be easily incorporated with relative ease. At last, a comparative evaluation suggests its superiority in terms of fault classification accuracy, fault detection time, diversify fault scenarios and computational requirement among other existing techniques. [ABSTRACT FROM AUTHOR]

Eastern Regional (ER) grid of India is one of the five regional grids consisting of voltage level 765 kV, 400 kV, 220 kV and numerous buses at lower voltage range. ER grid is the backbone of the Indian Grid as it is one of the main power generating hubs. Stability of the Indian Grid depends a lot on ER grid as it is the core of the generation and transmission system. For performing stability studies and to determine the weak area of the grid generally L-Index method is used. For detailed analysis like computation of voltage recovery time, maximum frequency deviation and critical clearing time of the buses of the system L-Index method is not suitable. Hence dynamic simulation is performed as it provides options to compute various parameters of ER Grid. The system has been studied using 197 buses of voltage levels 220 kV and above and transmission lines running over a length of 23,693 km. In this paper the power flow modelling, simulation and analysis of the Eastern Grid of India is performed. L-Index algorithm along with dynamic simulation provides the scope of computation of voltage recovery time, maximum frequency deviation and critical clearing time (by introducing an initial transient disturbance) along with the prediction of weak area of the system which gives a complete picture of transient stability of ER Grid. [ABSTRACT FROM AUTHOR]

The high compensation degree series compensation has a broad development prospects in long distance and large-capacity UHV transmission lines. But it is generating secondary arc current contains low frequency components with high amplitude when the single-phase grounding fault occurs in the series compensated transmission line, which is not conducive to rapid arc extinguishing. To solve this problem, this paper based on the mechanism of generating secondary arc by series compensation transmission lines, and using ATP – EMTP electromagnetic transient program to establish the simulation model of UHV series compensation device. And the suppression effects of small resistance short connection fault series compensation and linkage bypass series compensation measures on secondary arc current and recovery voltage under different series compensation layout mode are studied respectively. The results show that the attenuation speed of the secondary arc current is related to the series compensation arrangement modes and the time when the series compensation device is short connected or bypassed. Series compensation device short connected or bypassed before circuit breaker tripping which can accelerate the arc extinction speed, and the suppression effect is better when the series compensated double platform segmentation layout is distributed on both sides of the line. The results can be used as a reference for the engineering design of UHV with large capacity and long distance and high compensation series compensation transmission lines. [ABSTRACT FROM AUTHOR]

In this paper, a modern two stage frequency control approach for two area interconnected power system with doubly fed induction generator (DFIG) based wind turbine is proposed. For first stage, a proportional integral derivative (PID) controller is designed for every conventional thermal area to control frequency and tie line power. In the second stage, a PID controller is implemented in DFIG to regulate its speed and accordingly control system frequency particle swarm optimization is used to tune the controllers of conventional thermal units and DFIG. The effectiveness and robustness of the proposed control scheme are investigated under different operating conditions using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

With the continuous expansion of the scale of power system, corridor resources of overhead transmission lines tend to be saturated in China, making AC/DC erection on the same tower a trend in future development. The AC/DC coupling effect will cause DC line to generate secondary arc current at the point of failure when transmission line fails, which affects the DC restart. On account of the mechanism of generating secondary arc current by AC/DC lines erected on the same tower, this paper uses PSCAD to establish simulation model for AC/DC erected on the same tower. And the effects of different fault locations, lengths of coupling sections, and different transposition modes of AC lines on the secondary arc current and recovery voltage of AC and DC lines are studied. The results show that secondary arc current on DC line is greatly affected by fault location and length of coupling line, and using different transposition modes of AC lines can reduce secondary arc current on the DC lines effectively. According to Yunguang UHV DC restart time sequence, setting the restart time sequence can increase the first restart deionization time to ensure the stable operation of the system. [ABSTRACT FROM AUTHOR]

In this paper, some new sufficient conditions are established for the oscillation of all solutions of the second-order neutral differential equation with mixed neutral terms of the form (r(t)(x(t) + ax(t-τ) + bx(t + σ))′)′ + p(t)xα(t-k) + q(t)xβ(t + m)=0 for all t ≥ t0, under the condition .... The results obtained in this paper are new, and they generalize and complement some known results. Examples are provided to illustrate the main results. [ABSTRACT FROM AUTHOR]

This paper proposes a new type of generalized droop-based proportional power sharing scheme during load change for parallel inverter-interfaced islanded microgrids, which is an automatic strategy and is independent of any particular nature of transmission lines, i.e., resistive or inductive. Real and reactive powers are shared in proportion to the droop gains by implementing the voltage control law proposed in this paper; in which the inverter-interfaced voltage-sources are kept at equal reference values. The control gains are chosen based on eigenvalue analysis in a way that the system stability is ascertained. The performance of the designed controller is simulated under different microgrid structures such as load variation and various types of transmission lines; in which the results show superior dynamic performance in comparison to the conventional droop-based control strategy. [ABSTRACT FROM AUTHOR]

Occurrences of High Impedance Faults are common in Power Distribution between substation to substation, substation to rural area and within rural area. High Impedance Faults are detected based on Fault current measured by Fault Detection devices But an important fault is the Downed or Broken power line Fault not touching the ground cannot be detected when there is not enough faults current to operate fault detection devices in Over Head power distribution. Many methods to find High Impedance Faults exist. However, no proper method exists to find the Detection and location of Downed or broken power line Fault not touching the ground.Such a condition represents no electrical abnormality and till now its detection would probably have to depend on visual sighting. This paper proposes methods F-PLCCG and Hybrid AD method going to solve above problem. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal dynamic reserve activation plan after the occurrence of an emergency situation (generator/transmission line outage, load increase or both). An optimal plan is developed to handle the emergency situation, using coordinated action of fast and slow reserves, for secure operation with minimum overall cost. This paper considers the reserves supplied by generators (spinning reserves) and loads (demand-side reserves). The optimal backing down of costly/fast reserves and bringing up of slow reserves in each sub-interval in an integrated manner is proposed. The simulation studies are performed on IEEE 30, 57 and 300 bus test systems to demonstrate the advantage of proposed integrated/dynamic reserve activation plan over the conventional/sequential approach. [ABSTRACT FROM AUTHOR]

This paper presents a methodology to evaluate transient stability constrained available transfer capability (ATC). A linear and fast line flow-based (LFB) method was adopted to optimize the ATC values. This enabled the direct determination of the system source-sink locations. This paper formulated different market transactions considering bilateral and multilateral impacts in the stability constrained ATC. The proposed method was demonstrated on the WECC 9-bus and IEEE 39-bus systems. The critical energy performance index (CEPI) enabled the direct identification of candidates for contingency screening based on ranking. This index helped to reduce the list of credible contingencies for ATC evaluation and, therefore, the computation time. The results of the proposed ATC method are consistent with the literature and can be deployed for fast assessment of the impact of transactions in an electric power system. [ABSTRACT FROM AUTHOR]

This paper deals with line protection challenges experienced in a system having substantial wind generation penetration. Two types of generators, thermal synchronous generators and fixed speed wind turbines based on squirrel-cage induction generators, are simulated as thevenin equivalent model, connected to grid with single-circuit transmission line. The paper gives comparative discussion and summarizes analytical investigations carried out on the impedance seen by distance relays by varying fault resistances and grid short circuit MVA, for the protection of such transmission lines during faults. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of different bypassing schemes and grounding methods on the secondary arc current and the transient recovery voltage (TRV) of series compensated transmission lines. It is known that in series compensated lines, the peak value of the TRV may exceed the insulation strength. Furthermore, a secondary arc current is generated during a single line to ground fault mainly affected by the capacitive coupling between the healthy lines and the faulted line and can persist for seconds. The steadiness of secondary arc current prevents line reclosers from having a prompt closing to fulfill the system stability. This paper discusses different scenarios that can be employed to limit the secondary arc current consistency and to suppress a severe TRV during a single line to ground fault. A frequency domain analysis is conducted to better understand the nature of the secondary arc current. It is noted that an accurate arc model based upon the Kiziclay's arc model is used in the simulations. [ABSTRACT FROM AUTHOR]

Dynamic voltage restorer (DVR) is a custom power device used for voltage compensation of sensitive loads against voltage disturbances in power distribution lines. However the DVR spend most of its time in standby mode, since voltage sags occur very infrequently, and hence their utilization is low. In principle, it would be advantageous if the series connected converter based DVR could also be used to compensate for any steady state load voltage harmonics and power flow control in the line. This paper proposes a phase angle regulator which compensates the load voltage during sag with minimum distortions and also controls the flow of power in line when there is no disturbance in the feeder, through a phase adjustment technique. The compensation process is accompanied by an exchange of power between the DVR supported from wind energy conversion system and the grid. Controller works according to progressive phase advance strategy to correct voltage sag as well as power sharing between the DVR and the network as per available power from the wind. In this paper, different control strategies of dynamic voltage restorer are analyzed with emphasis put on the compensation of voltage sag and power flow control. The proposed control performance of the multi-functional DVR is verified through the PSCAD/EMTDC simulation studies. [ABSTRACT FROM AUTHOR]

This paper discusses problems and the possible solutions for protecting series compensated transmission line with distance relays. The paper also takes into consideration the influence of the series compensation on the distance relays installed on the short lines adjacent to the compensated line. Starting from visualising the response of the distance relays, the paper proposes some simple but novel methods to secure and improve the distance relay response. The methods include new impedance and direction determining techniques, placement of CVT and setting considerations. The material presented in this paper is based on the authors experience in protecting series compensated lines with distance relays. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the influence of voltage dependent load models on day ahead real power market clearing (DA-RPMC). The investigations clearly bring out the unsuitability of conventional single objectives such as production cost minimization (PCM) (or social welfare maximization (SWM)), due to reduction of load served. Hence, the multi-objective optimization is essential in this context. The paper proposes several objectives such as production cost minimization (PCM) (or social welfare maximization (SWM)), load served maximization (LSM), and Voltage Stability Enhancement Index (VSEI); which can be judiciously combined as per the needs of the operating condition. Multi-objective Strength Pareto Evolutionary Algorithm (SPEA) has been used to solve the DA-RPMC problem. The effectiveness of the proposed approach is tested on IEEE 30 bus system and the detailed simulation studies have been carried out by considering different operating conditions with voltage dependent load modeling. [ABSTRACT FROM AUTHOR]

In recent years, the UAV (Unmanned Aerial Vehicle) inspection for the electrical line has received increasing attentions due to the advantages of low costs, easiness to control and flexibility. The UAV can inspect the electrical tower independently and automatically by planning the flight path. But during the inspection along the path, the UAV is easily impacted by gust wind due to its light weight and small size, which always leads to the crash into the electrical tower. Thus, in this paper, a safe flight approach (SFA) is proposed to make the flight be safer during the inspection. The main contributions include: firstly, the piecewise linear interpolation method is proposed to fit the distribution curve of the electrical towers based on the GPS coordinates of the electrical towers; secondly, the no-fly zone on the both sides of the distribution curve are created, and a security distance formula (SDF) is raised to decide the width of the no-fly zone; thirdly, a gust wind formula (GWF) is proposed to improve the artificial potential field approach, which can contribute to the path planning of the UAV; finally, a flight path of the UAV can be planned using the SFA to make the UAV avoid colliding with the electric tower. The proposed approach is tested on the experiment to demonstrate its effectiveness. [ABSTRACT FROM AUTHOR]

The paper presents an on-line sequential extreme learning machine (OS-ELM) based fast and accurate adaptive distance relaying scheme (ADRS) for transmission line protection. The proposed method develops an adaptive relay characteristics suitable to the changes in the physical conditions of the power systems. This can efficiently update the trained model on-line by partial training on the new data to reduce the model updating time whenever a new special case occurs. The effectiveness of the proposed method is validated on simulation platform for test system with two terminal parallel transmission lines with complex mutual coupling. The test results, considering wide variations in operating conditions of the faulted power network, indicate that the proposed adaptive relay setting provides significant improvement in the relay performance. [ABSTRACT FROM AUTHOR]

This paper proposes a synchrophasors-assisted intelligent relaying scheme for transmission lines compensated by Unified Power Flow Controller (UPFC). The algorithm uses a new relaying signal termed as imaginary part of integrated impedance (IPII). The synchronized phasor measurements at both ends of the transmission line are used to extract voltage and current phasors from instantaneous voltage and current signals. The voltage and current phasors are utilized to derive IPII of each phase. Further, IPII of each phase is used as input to a data-mining model termed as decision tree (DT) which provides the final relaying decision. The proposed algorithm is validated on real-time digital simulator (RTDS) platform, and the results obtained indicate that the proposed scheme is both dependable and secure in protecting transmission system compensated by UPFC. [ABSTRACT FROM AUTHOR]

Transmission lines are essential components of electric power grids. Diverse power system applications and simulation based studies require transmission line parameters including series resistance, reactance, and shunt susceptance, and accurate parameters are pivotal in ensuring the accuracy of analyses and reliable system operation. Commercial software packages for performing power system studies usually have their own databases that store the power system model including line parameters. When there is a physical system model change, the corresponding component in the database of the software packages will need to be modified. Manually updating line parameters are tedious and error-prone. This paper proposes a solution for streamlining the calculation of line parameters and updating of their values in respective software databases. The algorithms used for calculating the values of line parameters are described. The software developed for implementing the solution is described, and typical results are presented. The proposed solution is developed for a utility and has a potential to be put into use by other utilities. [ABSTRACT FROM AUTHOR]

This paper presents a novel fault location method for transmission lines. The proposed method extends an existing method to locate faults by employing voltage and current measurements at one bus, which can be the bus of the faulted line or be far away from the faulted line. The method is applicable if a loop exists that encloses the faulted line, and the bus, of which the voltage is used, and the branch, of which the current is used. The during-fault positive-sequence bus impedance matrix is derived. Then superimposed voltages and currents due to the fault are expressed as a function of fault location and related transfer and driving point impedances. Consequently, the fault location can be evaluated using the obtained measurements. The distributed parameter line model is adopted to consider the shunt capacitances of the line. The proposed method is independent of fault resistance and fault type. Simulation studies have been carried out based on a 27-bus power system, and promising results have been achieved. [ABSTRACT FROM AUTHOR]

Overvoltages caused by switching operation of power system equipments might damage some equipment and delay power system restoration. This paper presents a comparison between transmission line (TL) models for overvoltages study and investigates which TL model is most proper for every case study. Both simulation time and accuracy factors of TL models are considered for selecting best TL model. Various cases of switching of transformer, shunt reactor, capacitor bank, and transmission line are investigated and simulation results for a partial of 39-bus New England test system, show that the proposed TL model evaluation increase accuracy and reduce simulation time (accelerate power system restoration) properly. [ABSTRACT FROM AUTHOR]

The National Electricity Policy (NEP) [], issued by the Government of India, mandates transmission prices to be distance and direction sensitive and capture utilization of the network by each network user. In line with the mandate, the Central Electricity Regulatory Commission (CERC) [] has issued Sharing of Interstate Transmission Charges and Losses Regulations, 2010 [], to introduce point of connection (PoC)-based transmission pricing methodology in India. The methodology under the above regulations introduces one of the major reforms of its kind in the Indian power sector and seeks to share the total transmission charges in proportion to respective utilization of the transmission system by different entities. In this paper, the authors have enumerated their experience gained from the implementation of PoC-based transmission pricing regime in India. Authors have also discussed various issues encountered in the process of implementation and the methodology adopted. [ABSTRACT FROM AUTHOR]

In this paper a comparative evaluation study is carried out for a 3-level, 5-level, 7-level thyristor based multi-level current reinjection (MLCR)current source converters (CSC) in terms of line current total harmonic distortion (THD) obtained, reinjection transformer requirements, reinjection switch ratings, reinjection control circuitry complexities. MLCR concept adds self commutation capability to thyristors, produces high quality line current waveforms and provides reactive power compensation in CSCs. Multi-level conversion is applied to generate the required optimum injection current which, when reinjected to the ac side reduces the line current THD. Extensive PSCAD/EMTDC simulations are presented for the comparing the different m-level reinjection schemes. [ABSTRACT FROM AUTHOR]

This paper presents the operation under fault and protection of multi DC smart grids connected to the DC transmission line. The smart grid consists of wind turbine and photovoltaic generators, controllable loads, generator side and grid side inverters. The voltage stability of the DC bus voltage is attained by applying the power consumption control of controllable loads, the power control of grid connected converter and power control of renewable plants. On the other hand, the fault protection for short-circuit and low resistance ground fault at the DC transmission line was sighted. Simulation results based on PSIM are provided to demonstrate the effectiveness of the system. [ABSTRACT FROM AUTHOR]

Dynamic transmission network expansion planning (DTNEP) decides when (which year) and where (which R.O.W.), the new lines are to be built so that the overall cost of the plan is minimum and the system is secure. Generally, this is done for a fixed time horizon window (3/5 years) at a time. DTNEP has been proved to be better than the incremental approach in which optimal investment plans are found out for each year separately. In DTNEP, 1st year and last/terminal years are given different treatment, and there is a complete disconnect between two DTNEP windows. Also DTNEP assumes that the conditions during optimization like the earlier year generation, transmission expansion plans get\ executed exactly as per plan &/or the load forecast for the entire period remains unchanged. However, it is well known that this is generally not true. In view of above, this paper presents a rolling window based approach which treats every year of investment in exactly the same fashion. It also has an inherent capability to take care of such changes. It involves successive, overlapping DTNEP for 3/5 years planning horizon. A harmony search algorithm is used for the solution of the problem. Results for two test systems have been obtained to demonstrate the potential of the algorithm. [ABSTRACT FROM AUTHOR]

Transmission line parameters are essential inputs to various power system analysis programs and applications such as protective relaying algorithms, and precision of line parameters is thus significant in ensuring the analysis accuracy and algorithm reliability. This paper proposes methods for estimating positive sequence parameters of a series compensated transmission line. The methods are based on distributed parameter line model and utilize voltages and currents from both terminals of the line during normal operations. In particular, based on nonlinear estimation theory, an optimal estimator is designed for deriving positive sequence line parameters. The algorithm is capable of detecting and identifying bad measurement data, and thus improving the estimation accuracy. The proposed method is independent of the operation status of the compensation device. [ABSTRACT FROM AUTHOR]

There is an attempt to correlate the public health risk with strong magnetic fields from high voltage multiple transmission lines. The statement is based on the public perception that multiple sources of two and three tower lines can generate more radiated fields as compared to single tower. This paper evaluates the fact and figures on realistic situation cases about radiated field exposures based on measurements and simulation models of two and three transmission lines. The case study sites which consist of several towers of 132kV and 275kV lines were located in Melaka district, Malaysia. Measurement procedures of magnetic fields were conducted based on the IEEE/ANSI 644 standard while the dose exposure reference value was based on the public exposures of the ICNIRP limits. The results obtained from this analysis are then compared with the ICNIRP standard for assessing the significance of dose exposure between actual conditions in TNB systems with optimum simulated models of phase arrangements. Recommendations on the threshold value limits at both ROW for the new and existing transmission lines were also proposed in conjunction with development of TNB ELF-EMF policy guidelines. [ABSTRACT FROM AUTHOR]

This paper presents a scheme for the protection of parallel transmission line having two different configurations (geographical locations). In the proposed scheme, the six line currents at a common end of a parallel line or three line currents at a separate end of a parallel line are decomposed using wavelet packet transform (WPT) in order to derive the operating quantities for relay operation. The proposed scheme provides stability against close-in faults, more sensitivity towards high resistance faults and reliability for discriminating in-zone and out-zones faults during complete loss of generation at one of the buses. When the conventional relay, without an intuitive directional element, fails to trip for a remote end fault located in the vicinity of remote bus, the proposed method solves the said problem and also avoids the voltage signal used in conventional relays. Furthermore, the suggested scheme completely avoids the requirement of a distance algorithm as a backup protection in case of the disconnection of one line (due to maintenance or fault). Moreover, the proposed scheme analyzes solves the problem of simultaneous same phase fault on parallel lines. To validate the proposed scheme, numerous computer simulations have been carried out on realistic data of part of the Indian 400 kV power transmission system network. [ABSTRACT FROM AUTHOR]

The paper describes an electric field measurement method based electroscope system to check the electrification state of ultra-high voltage transmission lines, which is composed of three parts: 1) Measuring terminal; 2) Central sever; 3) GPRS and Internet network. The measuring terminal was used to measure the electric field and the location of the measuring points, then the measured data was sent to the central sever by GPRS and Internet network, and requested for an electricity state confirmation. When the sever received a request from a terminal, the electric fields and locations of the measuring points were obtained first, then according to the location of the measuring points, the server searches the corresponding objective transmission lines in the database and read their parameters. According to the parameters of the measuring points and transmission lines, a calculation would be carried out to confirm the electrification state of the transmission lines. For the confirmation calculation, equations for the electric field inverse problem of the transmission lines were set up first, then global regularization and damped Gauss Newton (DGN) method were used to solve the inverse problem. A 500kV double loops transmission line was taken as an example to verify the validity of this method. The electric field and location of 11 measuring points were measured by the measuring terminal firstly, and then sent to the central sever. Electrification state was confirmed by the central sever. [ABSTRACT FROM AUTHOR]

The need for dynamic loading of overhead lines requires reliable assessment tools that should be able to predict both the evolution of the hot-spot temperature and the associated maximum allowed duration, at any load level and on the basis of the actual conductor thermal state and environmental conditions. In order to address this problem, the paper proposes the employment of a smart sensor network distributed along the line route. Each network's node, starting from on-line measurements, assesses, by an indirect method of parameter identification, the value of the main variables which regulate the heat exchange between the conductor and its surrounding. Then, starting from these data, each node calculates the load capability curve by solving iteratively a built in dynamic thermal model and transmits the results to a central server by a cooperative based communication paradigm. To assess the performances of the proposed solution, experimental studies obtained on a laboratory overhead line are presented and discussed. [ABSTRACT FROM AUTHOR]

This paper presents the results of an investigation on evaluating room-temperature-vulcanized (RTV) silicone rubber coatings for high-voltage insulators of substations and overhead transmission lines. It is based on tests conducted for three different available RTVs that are currently used by utilities. The study compared three commercial coatings: RTV-A and RTV-B filled with ATH (aluminum tri-hydrate) as the primary filler, and RTV-C filled with silica. The relative comparison between them is based on their electrical and chemical characteristics. The evaluation employed standard and research-based evaluation methods, including the salt fog test, the inclined plane test, thermo-gravimetric analyses (TGA), thermal conductivity measurement, soaking in water, the mechanical test, and SEM photographs. Results of the inclined plane test showed that the silica-filled coating is not resistive against tracking and erosion compared with ATH-filled coatings. It was observed that filler size is one of the main reasons for better performance of RTV-A compared with RTV-B, whereas both have ATH as the primary filler. The higher thermal conductivity of RTV-A resulted in a very good performance in the salt fog test and the IPT. [ABSTRACT FROM AUTHOR]

This paper describes a new iterative method to locate fault on a single transmission line. The method uses synchronized voltage and current measurements from both line terminals. Using the positive sequence components of the pre-fault and the post-fault phasors, positive sequence source impedances at both terminals are first estimated. Using these source impedances and the line data, the positive sequence bus impedance matrix (Zbus) is formed. Using the properties of Zbus, an iterative algorithm is proposed to locate the fault. This algorithm is tested extensively with data obtained from the EMTP simulation of a long transmission line simulated with distributed parameters in the presence of fault resistance and CT saturation. The simulation results show that the method is very accurate and robust. [ABSTRACT FROM AUTHOR]

The security of the transmission system is dependent on the relays' performance after various disturbances. Undesirable relay operation will trip the lines and lead to cascading events. In this paper the operation margin of mho relays is equivalently redefined as function of bus voltages instead of line impedance. The sensitivities of the operation margin to bus voltage and bus power is applied to quantify the vulnerability of transmission system. The contribution of the shunt compensation by SVC is analyzed based on the sensitivities (control factors) of the operation margin to the shunt susceptance. It is found that the control effect of SVC is approximately linear when the mho relay has relative smaller operation margin. In this range the linear model based on the control factors is accurate enough to simulate the control effect. It is also found that the shunt compensations at different locations may yield opposite effect to the operation margin of the mho relays, which can be easily judged by the value of the control factors. [ABSTRACT FROM AUTHOR]