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This paper investigates the applicability of IEC 61850-9-2 LE-sampled values in transients-based protection by implementing a line protection intelligent electronic device (IED), incorporating a transients-based hybrid protection algorithm suitable for series-compensated transmission lines. The IED is capable of subscribing, decoding, and processing sampled values to be used in the implemented protection algorithms. The proposed method of protection can distinguish between internal and external faults by comparing the polarities of wavelet coefficients of the line currents at either end of the line. The power system section, which the proposed protection scheme is tested upon, is implemented in a real-time digital simulator. Attention is given to replicate the constraints faced by an actual relay in the implementations of the IED. The results indicate that IEC 61850-sampled values can be effectively used in a transients-based protection scheme that is capable of operating under challenging conditions. [ABSTRACT FROM PUBLISHER]

The protection of active distribution networks incorporating microgrids with high penetration of Distributed Energy Resources (DERs) can be challenging if traditional protective relays are used. This is mainly due to the changes in the power flow, fault current level, difficulty in protection coordination, changes in system topology, and system operating conditions. This paper proposes three new protection algorithms for active distribution networks with large penetration level of inverter-based DERs. These protection algorithms comprise of an adaptive differential protection algorithm, incremental transient energy-based directional protection, and a rate-of-change of current protection. The proposed protection algorithms were tested with a distribution network integrated with wind, solar, diesel generator, and battery storage DERs which are capable of operating in islanded mode forming local microgrids. The distribution system and the proposed protection functions modelled and simulated using the Real-Time Digital Simulator (RTDS®). The results obtained from tests validate the proposed algorithms; and their capability to correctly detect and timely isolate faults without resulting in nuisance tripping of the DERs. [ABSTRACT FROM AUTHOR]

This paper presents the development and hardware implementation of a classification scheme to distinguish the transients originated by faults from other types of transients. In the proposed scheme, a set of Hidden Markov Model-based classifiers is employed to recognize the fault transients. Input features for the classifiers are the energy contained in wavelet coefficients of the measured current waveforms. A laboratory prototype of the fault recognition system was implemented on a floating-point digital–signal-processor (DSP)-based hardware platform. The classification system was tested using the transient signals generated by a real-time waveform playback unit. The test waveforms were generated by simulating an actual extra-high-voltage transmission system on an electromagnetic transient simulation program. The operation of the classification system was further verified using waveforms obtained from an actual fault recorder. The performance of the classifier was investigated under different practical scenarios, such as current transformer saturation, measurement noise, and lightning faults. [ABSTRACT FROM PUBLISHER]

This paper presents a novel algorithm to determine the location of dc line faults in an HVDC system with a mixed transmission media consisting of overhead lines and cables, using only the measurements taken at the rectifier and inverter ends of the composite transmission line. The algorithm relies on the traveling-wave principle, and requires the fault-generated surge arrival times at two ends of the dc line as inputs. With accurate surge arrival times obtained from time-synchronized measurements, the proposed algorithm can accurately predict the faulty segment as well as the exact fault location. Continuous wavelet transform coefficients of the input signal are used to determine the precise time of arrival of traveling waves at the dc line terminals. Two possible input signals–the dc voltage measured at the converter terminal and the current through the surge capacitors connected at the dc line end–are examined and both signals are found to be equally effective for detecting the traveling-wave arrival times. Performance of the proposed fault-location scheme is analyzed through detailed simulations carried out using the electromagnetic transient simulation software PSCAD. The impact of measurement noise on the fault-location accuracy is also studied in this paper. [ABSTRACT FROM PUBLISHER]

The paper first shows that the transient stability status of a power system following a large disturbance such as a fault can be early predicted based on the measured post-fault values of the generator voltages, speeds, or rotor angles. Synchronously sampled values provided by phasor measurement units (PMUs) of the generator voltages, frequencies, or rotor angles collected immediately after clearing a fault are used as inputs to a support vector machines (SVM) classifier which predicts the transient stability status. Studies with the New England 39-bus test system and the Venezuelan power network indicated that faster and more accurate predictions can be made by using the post-fault recovery voltage magnitude measurements as inputs. The accuracy and robustness of the transient stability prediction algorithm with the voltage magnitude measurements was extensively tested under both balanced and unbalanced fault conditions, as well as under different operating conditions, presence of measurement errors, voltage sensitive loads, and changes in the network topology. During the various tests carried out using the New England 39-bus test system, the proposed algorithm could always predict when the power system is approaching a transient instability with over 95% success rate. [ABSTRACT FROM PUBLISHER]

A new type of sensor is proposed to detect high frequency transients in currents and their initial polarities. The proposed sensing system replaces both high frequency signal sampling and processing by a simple detection coil wound on a ferrite core and an analogue electronic circuit. It is verified through laboratory experiments that transient occurrence, occurrence time, and initial transient polarity can be determined accurately. A detailed model of the sensor, including the dynamic hysteresis characteristics of the ferrite core, is developed and implemented on an electromagnetic transient simulation software, and verified through experimental measurements. Application of the developed model to simulate a transient current polarity comparison based protection scheme is demonstrated. The versatility of the proposed sensor compared to common digital signal processing based approaches, namely discrete wavelet transform and mathematical morphology, is highlighted using experimental waveforms. [ABSTRACT FROM AUTHOR]