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• A novel, non-pilot scheme to avail Accelerated Trip (AT) signal using local measurements for the distance relays. • Method based on total relative reactance change – not requiring any extra hardware for implementation. • Fast operation of a non-pilot method comparable with permissive transfer trip signal delays. • Testing of methods in varying types of contingencies to ensure correct operation such as evolving high impedance fault and remote-end breaker arc re-striking. • Confirmation of the tests with relay data record-timing diagrams discussed in the protection subcommittee meeting, NRPC, India. Challenges about the accurate impedance measurement comply pessimistic setting of distance relay reach. Hence, internal, remote-end faults from either end of the connected power system's protected line section are cleared with a prolonged time delay. Although carrier communication-aided protection schemes can accelerate the relay operation, latency in data transmission and link failure hampers the reliability of communication-assisted TRIP schemes. The present article analyzes the adverse effects of the inadvertently long fault clearing time due to the contingent communication-assisted transfer trips. To overcome the challenges by minimizing fault clearing time, the paper proposes a simple yet effective method of monitoring the total relative reactance change seen by the relay to discriminate between internal and external faults to the protected line section and consequently issue of Accelerated Trip (AT) signal for internal faults without communication assistance. The method monitors the total relative change of reactance over the specified time window and compares the same with the threshold to discriminate between internal and external faults. In addition, a steady state difference between the apparent values of the measured reactance is used to improve the robustness of the proposed algorithm further. The method has shown robustness against a wide range of fault resistance and fault types. Moreover, extensive unique tests are carried out and reported such as AT issue stability during remote-end breaker arc re-ignition for internal faults, sudden change in fault resistance during the detection window, and the fault on mutually coupled parallel line section. The method issues AT signal in 70 ms from the point of fault inception, comparable with the permissive transfer trip signal delay. Moreover, the AT signal issue is independent of the fault MVA for the remote end, internal faults, and the mutual inductance due to coupled parallel lines. The timings for the fault inception to clearing process are referred from relay data records presented in the protection sub-committee meeting of the Northern Region Power Committee (NRPC), India. The modeling and simulations are carried out using PSCAD software and the algorithm is tested with MATLAB. [ABSTRACT FROM AUTHOR]

Conventional load flow algorithms are very commonly used in the system planning. In the conventional load flow methods, system electrical parameters at specific weather conditions will be considered. These methods gives results for given loading condition and have no provision to incorporate weather condition of a specific geographical location. If the load flow has the provision to incorporate the dynamic electrical characteristics of the conductors based on the operating weather condition, the results of the methods are going to be more accurate or in other words the results are close to the real values. In view of the above, in this paper a modified load flow algorithm incorporating the thermal modeling of the conductors with ambient temperature, wind velocity, conductor surface absorptivity, global solar radiation, Wind direction factor etc. is proposed. To verify the effectiveness of the proposed algorithm, the thermal mathematical model of transmission lines available in IEEE Std. 738™ -2006, IEEE Std. 738™ -2012 and CIGRE WG 22.12 are considered. In the proposed algorithm, new variables corresponding to Conductor Temperature are incorporated. The proposed algorithm is tested with the real time weather data of India and demonstrated on IEEE 30 and 118 bus systems. • An algorithm for power flow including thermal models of the transmission lines. • Variable weather and ZIP load models are incorporated in the proposed algorithm. • It estimates the transmission line temperature using the field measurements. • Seasonal variations of the critical bus voltages are estimated using proposed method. • Impact of renewable generation on system performance is evaluated. [ABSTRACT FROM AUTHOR]

• A hybrid algorithm applying ST, HT and RBDT is designed for recognition of multiple PQ disturbances. • Designed HPQI and HPLI indices effectively detect and localize the CPQDs. • Proposed RBDT supported decision rules driven by features computed from HPQI and HPLI effectively classified the CPQDs. Classification accuracy higher than 98% is achieved. • Performance of algorithm is better compared to HT and RBDT based technique. • Algorithm is validated to recognize CPQDs incident on practical distribution network. Hence, it can be incorporated in online PQ monitoring devices. This paper proposes an algorithm based on the Stockwell transform (ST) and Hilbert transform (HT) to classify complex power quality disturbances (CPQDs). Two indices are used for detection and locating the CPQDs. The first index is the hybrid power quality index (HPQI), which is used to classify CPQDs. The Stockwell maximum values factor (SMVF), Stockwell summation values factor (SSVF), and Stockwell variance values factor (SVVF) are computed by utilizing the ST to process a voltage signal having a superimposed PQ disturbance. To compute the Hilbert index (HI), the voltage signal is also processed using the HT. The HPQI index is calculated by element-to-element multiplication of the SMVF, SSVF, SVVF, HI, and a weight factor (WF). The second index is the hybrid power quality disturbance time localization index (HPLI), which is used to locate the complex PQ events in a given time frame. For classification of investigated CPQDs, seven different features extracted from various indices defined using ST and HT are taken as input to the rule-based decision tree (RBDT). RBDT classifies the disturbances using simple decision rules, which has the merit of low computational time. The algorithm is able to correctly detect CPQDs with a 98% accuracy rate. The proposed algorithm outperforms the literature's algorithm, which is based on HT and RBDT. Furthermore, it is demonstrated that the algorithm effectively recognizes CPQDs that occur in real-time on a practical distribution network in Rajasthan State, India. [Display omitted] [ABSTRACT FROM AUTHOR]

• Bringing the asset management of transformer under the purview of building manager from utility. • Derived mathematical model of demand response from transformer thermal model. • Method to estimate transformer temperature time constant from measurements and algorithm for improving the life of transformer by regulating HVAC and AHUs. • Smart grid architecture for demand responsive HVAC. • Real time simulation of impact of demand response using the actual building consumption data from an academic campus. Overloading and ageing effects contribute to 12-15% of distribution transformer failures in India. This research is motivated in extending life of transformer by using demand response as an operational strategy where the demand response events are issued by predicting overheating of transformer before it occurs. In this paper heating ventilation and air conditioning is considered as a flexible load for responding to demand response events. A demo site is created at 11 KV/440 V substation with 1.6 MVA transformer at Indian Institute of Technology Hyderabad (IITH) campus and the proposed architecture and algorithm is implemented. This substation supplies power to chiller plant and three academic buildings with heating ventilation and air conditioning (HVAC). Analysis for improving the transformer lifetime is carried out for 5 consecutive days during the period (25–29)th Feb 2020 using real time field data. It is observed that during this period 11 demand response events occurred with a total demand response of 919 kWH. From the obtained results it is observed that there is a saving of 15 hoursof transformer life within a period of 5 days (120 hours) of transformer operation. The key contribution in this paper is to bring together three concepts transformer lifetime estimation, HVAC flexibility and demand response for improving the transformer lifetime. [ABSTRACT FROM AUTHOR]

• FPGA based EMT simulation framework for the power distribution network is presented. • Conjugate-gradient based electrical network solver is implemented. • Simulation framework is validated for the Jail substation of Guwahati city, India. • Results are compared with the MATLAB based EMT implementation. The electrical power distribution network (PDN) is in the transition phase due to the integration of distributed energy resources (DERs). Therefore, an accurate and efficient modeling and simulation platform is the need of the hour to determine the dynamic behavior of the PDN. The recent computational hardware, such as GPU, FPGA, etc. enables new simulation paradigm and develop a more realistic platform in the form of system emulators. In this paper, an FPGA based electromagnetic transient (EMT) simulation framework for the PDN is presented. Conjugate-gradient (CG) based electrical network solver is implemented in the proposed framework, and a test case is analyzed for Jail substation of Guwahati city, India, to validate the simulation environment. It has been compared with the MATLAB based implementation for verifying its accuracy. The proposed EMT simulator is approximately 12.5 times faster as compared to its MATLAB implementation and exhibits good accuracy as well. [ABSTRACT FROM AUTHOR]