Search

This paper addresses the subject of reducing outage durations and autorestoration applications within the distribution substation. Employment of intelligent electronic devices (IEDs) can aid in the reduction of the fault duration time, and also it enhances the protection, control, and monitoring at the distribution level. Further, communication among these IEDs can provide faster autorestoration, remote data analysis, event recording, etc. Many recent issues related to distribution substation protection are discussed and techniques to address these issues using current technologies are proposed. [ABSTRACT FROM AUTHOR]

Local distribution companies (LDCs) require disconnection of distributed generation (DG) as soon as disturbance events occur to prevent sustainable islanding and damaging DGs and other equipments. In this paper, real-time laboratory testings were carried out to evaluate existing anti-islanding detection schemes. A comprehensive analysis and a testing process are proposed to assess the selection of a fast and reliable scheme for a practical radial distribution system equipped with a group of self-excited induction generator wind turbines (SEIG). Two antiislanding schemes (passive local detection and communication based) were examined on various commercial relays to disconnect SEIG-DG in case of a main breaker opening due to a fault. The impact of existing recloser timer characteristics on the selection of the proper scheme is illustrated. The selected scheme was verified to disconnect SEIG-DGs in case of amanualmain breaker opening in a proper time to protect public safety. A dedicated fiber optic connection and radio frequency communication-based schemes were evaluated and compared with passive local detection scheme performance. Various scenarios of SEIG-DG penetration levels were simulated, and different available commercial relay functions were tested. The obtained results, recommendations, and economic evaluations for choosing a proper scheme are reported and discussed. [ABSTRACT FROM AUTHOR]

A new approach is proposed to solve the directional overcurrent relay coordination problem, which arises from installing distributed generation. (DG) in looped power delivery systems (PDS). This approach involves the implementation of a fault current limiter (FCL) to locally limit the DG fault current, and thus restore the original relay coordination. The proposed restoration approach is carried out without altering the original relay settings or disconnecting DGs from PDSs during fault. Therefore, it is applicable to both the current practice of disconnecting DGs from PDSs, and the emergent trend of keeping DGs in PDSs during fault. The process of selecting FCL impedance type (inductive or resistive) and its minimum value is illustrated. Three scenarios are discussed: no DG, the implementation of DG with FCL and without FCL. Various simulations are carried out for both single- and multi-DG existence, and different DG and fault locations. The obtained results are reported and discussed. [ABSTRACT FROM AUTHOR]

In this paper, a new system splitting scheme based on the unified stability control framework is proposed. Compared with the conventional system splitting scheme, the new method is much more effective under complicated oscillation scenarios. Under the unified stability control framework, different emergency control measures can be evaluated and compared with each other. The system splitting strategy will be applied to the system only when the analysis shows that the splitting is necessary or reasonable. Related algorithms are described in detail in this paper. The advantages and effectiveness of the new scheme can be justified through the testing cases. [ABSTRACT FROM AUTHOR]

Phasor estimation algorithms for protective relaying are required to filter out unwanted components from the input signals and retain only the components of interest. The components to be removed include harmonics and the decaying-exponential transient (dc offset) component. They affect the accuracy and the speed of convergence of the phasor estimation algorithms to a great extent This paper presents a new technique, which effectively removes the harmonics and the decaying dc component present in the input signals, within half a cycle of the power system frequency. This is achieved by means of a simple computational procedure using three off-line look-up tables. The proposed algorithm has been tested for a wide variety of signals to assess its performance. The performance is also compared with the two most popular half-cycle phasor estimation algorithms; the half-cycle least error squares algorithms and the mimic plus half-cycle Fourier algorithm. The test results show that the proposed relaying algorithm has a faster convergence and better accuracy compared to these previously proposed algorithms. The results also indicate that the proposed algorithm converges to its final value within half a cycle of the power system frequency as compared to the other two algorithms, which take more than half a cycle to converge, when a decaying dc component is present in the input. [ABSTRACT FROM AUTHOR]

Proposes a system modeling concept and an algorithm based on abductive inference for handling diagnostic problems in electrical power transmission networks. Scope of the system modeling technique and the algorithm; Basic concepts of the proposed technique; Fault diagnosis using abductive inference; Fault diagnosis algorithm; Test results of the proposed technique; Processing speed of the diagnosis module; Conclusions.

Different factors affect solar photovoltaic (PV) systems by decreasing input energy and reducing the conversion efficiency of the system. One of these factors is the effect of snow cover on PV panels, a subject lacking sufficient academic research. This paper reviews and compares current research for snow removal in solar PV modules. Additionally, this paper presents the design, analysis and modelling of a smart heating system for solar PV Electric Vehicle (EV) charging applications. The system is based on a bidirectional DC-DC converter that redirects the grid/EV-battery power into heating of the solar PV modules, thus removing snow cover, as well as providing the function of MPPT when required to charge the EV battery pack. A control scheme for each mode of operation was designed. Subsequently, a performance evaluation by simulating the system under various conditions is presented validating the usefulness of the proposed converter to be used in solar PV systems under extreme winter conditions. [ABSTRACT FROM AUTHOR]

In this paper, a hybrid fuzzy cascaded fractional order proportional integral-fractional order proportional derivative (FCFOPI-FOPD) controller improves the frequency regulation of a renewable energy source (RES) integrated power system. The frequency response characteristics of a two-area non-linear thermal-hydro-wind model under various operating situations are explored with an emphasis on the extensive usage of renewable energy sources (RES) in modern power systems. The power system in this study is developed using an innovative combination of a standard dynamic model of the steam turbine and the actual physical position of the generation rate constraint in the power plant model. The suggested FCFOPI-FOPD hybrid controller minimizes a power system's frequency deviation caused by specific differences in the pre-scheduled load. The effectiveness of a proposed FCFOPI-FOPD hybrid controller in alleviating system frequency variations under various perturbations was determined using MATLAB Simulink analysis. Comprehensive results show that the FCFOPI-FOPD hybrid controller outperforms the fuzzy-structured fractional order proportional integral and derivative (FOPID) and the proportional and integral controllers. The results also demonstrate that the proposed controller improves the settling time of frequency variations in area-1, area-2, and tie-line power deviation by 47%, 51%, and 66% compared to the responses obtained with the fuzzy FOPID controller. [ABSTRACT FROM AUTHOR]

This paper proposes the use of an intrusion detection system (IDS) tailored to counter the threats to an IEC61850-automated substation based upon simulated attacks on intelligent electronic devices (IEDs). Intrusion detection (ID) is the process of detecting a malicious attacker. It is an effective and mature security mechanism. However, it is not harnessed when securing IEC61850-automated substations. The IDS of this paper is developed by using data collected by launching simulated attacks on IEDs and launching packet sniffing attacks using forged address resolution protocol (ARP) packets. The detection capability of the system is then tested by simulating attacks and through genuine user activity. A new method for evaluating the temporal risk of an intrusion for an electric substation based upon the statistical analysis of known attacks is also proposed. [ABSTRACT FROM PUBLISHER]

This paper proposes a scheme for auditing the security of an IEC61850-based network based upon a novel security metric for intelligent electronic devices (IEDs). A detailed security analysis on an IEC61850 automated substation is peformed initially with a focus on the possible goals of the attacker. This is followed by the development of a scheme to audit the security of such a network. Security metrics are considered since they provide a tangible means of quantifying the security of a network. The proposed auditing scheme is tested by using it to audit the security of an IEC61850 network. The results are then compared with two other metric schemes—the mean time to compromise (MTTC) metric and the VEA-bility metric, which are used for auditing conventional computer networks. The input data for both metrics are obtained by using a network security tool to scan the IEDs of the network. The impact of using high-traffic generating network security tools on a time-critical IEC61850 network is also investigated. [ABSTRACT FROM PUBLISHER]

Breaker failure (BF) protection provides backup for circuit breakers (CBs) and associated control wiring. Traditionally, CBs are not duplicated, but monitored by BF relays when ordered to trip. Upon a failure of a breaker to interrupt the current, the BF relay opens adjacent breakers to isolate the problem. The total trip time under a BF condition is often tightly fit into the critical fault clearance time as determined by system stability. With narrow stability limits in today's power systems, coordination margins for the operation of BF functions are becoming scarce. This imposes a requirement for the fast reset time of BF protection. In its first part, this paper presents a novel algorithm for numerical current-based BF function with a fast 0.5-cycle reset time even under severe subsidence current. In the second part, the paper addressed the problem of fast and secure recognition of binary inputs for both BF initiation and BF detection based on the auxiliary breaker contacts. This novel algorithm works with analog representation of binary signals and provides security under induced transients, battery ground faults, and other interfering events. [ABSTRACT FROM AUTHOR]

• This paper discusses the applications of smart meters for protection and monitoring of emerging active distribution systems in a smart grid environment. • A number of possible applications are suggested and each of the suggested application can eventually become a research project. • This paper is of seminal nature in the area of smart meters and once published, will get a lot of air. Emerging distribution systems are experiencing large proliferation of smart meters. However, many groups have expressed reluctance in implementing the idea of smart meters. Health hazard due to exposure to radio waves, fire risk, security and privacy of customer information are some of the concerns raised by the consumers. Another important concern is the increased expenses of the utility providers with limited benefits resulting from detailed cost-benefit-analysis. Existing applications of smart meters have not been able to justify the importance of it in some situations. As evidenced in many articles, world-wide roll-out projects and the implementations of smart meters have been hindered with obstacles many times. Therefore, this sluggish progress and growing negative concerns originate the requirement of enhancement of new applications of smart meters in areas such as protection and monitoring of emerging distribution system. Protection and monitoring of distribution systems are two major aspects that any distribution provider is always concerned of and interested to explore smart approaches for management of it. This paper is proposing some potential applications in protection and monitoring of distribution system by the means of smart meters. The underneath expectation is that it will facilitate the required justifications in order to promote the future smart metering projects. [ABSTRACT FROM AUTHOR]