Performance of an adaptive protection scheme for series compensated EHV transmission systems using neural networks

In this paper, a static synchronous series compensator (SSSC), along with a fixed capacitor, is used to avoid torsional mode instability in a series compensated transmission system. A 48-step harmonic neutralized inverter is used for the realization of the SSSC. The system under consideration is the IEEE first benchmark model on SSR analysis. The system stability is studied both through eigenvalue analysis and EMTDC/PSCAD simulation studies. It is shown that the combination of the SSSC and the fixed capacitor improves the synchronizing power coefficient. The presence of the fixed capacitor ensures increased damping of small signal oscillations. At higher levels of fixed capacitor compensation, a damping controller is required to stabilize the torsional modes of SSR.

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Torsional interaction studies on a power system compensated by SSSC and fixed capacitor

This paper presents a new approach for the protection of Thyristor-Controlled Series Compensator (TCSC) line using Support Vector Machine (SVM). One SVM is trained for fault classification and another for section identification. This method use three phase current measurement that results in better speed and accuracy than other SVM based methods which used single phase current measurement. This makes it suitable for real-time protection. The method was tested on 10,000 data instances with a very wide variation in system conditions such as compensation level, source impedance, location of fault, fault inception angle, load angle at source bus and fault resistance. The proposed method requires only local current measurement. Keywords—Fault Classification, Section Identification, Feature Selection, Support Vector Machine (SVM), Thyristor-Controlled Series Compensator (TCSC)

/pdf/accurate-fault-classification-and-section-identification-s658o596z5.pdf

Accurate Fault Classification and Section Identification Scheme in TCSC Compensated Transmission Line using SVM

In this paper the behavior of fixed series compensated extra high voltage transmission lines during faults is simulated. Many over-voltage protection schemes for series capacitors are limited in terms of size and performance, and are easily affected by environmental conditions. While the need for more compact and environmentally robust equipment is required. use of series capacitors for compensating part of the inductive reactance of long transmission lines increases the power transmission capacity. Emphasis is given on the impact of modern capacitor protection techniques (MOV protection). The simulation study is performed using MATLAB/SIMULINK®and results are given for a three phase and a single phase to ground fault. Keywords—Series compensation, MOV protected series capacitors, balanced and unbalanced faults

/pdf/simulation-of-series-compensated-transmission-lines-3xkb45fft3.pdf

Simulation of Series Compensated Transmission Lines Protected with Mov

Torsional Interaction Studies on a Power System Compensated by SSSC and Fixed Capacitor

The development of flexible AC transmission systems (FACTS) technology offers better opportunities to utilize existing transmission systems. One of the key FACTS devices is controllable series capacitor compensation (CSC). The authors discuss the digital simulation of CSC protection schemes. A parallel protective device is required to provide overvoltage limitation during system faults. There are two approaches adopted by utilities: one involves the combination of a traditional gap and a mechanical bypass switch; the other involves the use of varistor technology, in which the varistor is connected directly in parallel with the capacitor and provides fault overvoltage protection. With the incorporation of the components of a 500 kV series-compensated system into the Electromagnetic Transients Program (EMTP), the authors present some simulation results and the analysis of the system waveform patterns under various conditions. The studies show that under fault conditions, the operation of the capacitor gap or varistor does not conform to any clearly defined pattern.

Q.Y. Xuan

Papers

Digital simulation of series-compensated EHV (extra high voltage) transmission systems