Dynamic compensation of capacitive voltage transformers

Abstract

This paper presents the digital algorithm for on-line dynamic compensation of the secondary voltage of a Capacitive Voltage Transformer (CVT). The adopted CVT model together with the assumed simplifications is given first. Next, the compensating algorithm based on digital inversion of the CVT transfer function is derived Frequency domain analysis and quantitative evaluation of the compensation follow. The ATP-EMTP simulations are included that show the improvement of the measurement of protective criteria quantities as a result of dynamic compensation of a CVT.

Line voltage phasor reconstruction on capacitive voltage transformers using dynamic phasor approach

“…4.3.5. Statistical analyses compared with ANN (Zadeh and Li 2008) In this section, the statistical analyses are used to compare with previous works (Hou and Roberts 1996;Izykowski et al 1998;He, Li, andBo 2006 andZadeh andLi 2008). Among these works, ANN (Zadeh and Li 2008) indicates that most of the errors are less than 2%, which is the most accurate method in previous works.…”

“…However, this technique requires two-cycle samples for ANN computations, which may postpone the relay response. Considering previous works (Hou and Roberts 1996;Izykowski et al 1998;He, Li, and Bo 2006;Zadeh and Li 2008), there is still a motivation to develop a faster and more accurate algorithm to reconstruct line voltage phasors from CVT measurements during a fault period.…”

“…Over the last decade, several methods (Hou and Roberts 1996;Izykowski et al 1998;He, Li, and Bo 2006;Zadeh and Li 2008) have been presented to mitigate the impact of CVT transient. Hou and Roberts (1996) proposed a method to insert a suitable delay period to ignore CVT transients by source impedance ratio detections.…”

“…However, this method did not correct CVT measurements and such a relay might require a longer response time. A compensator was proposed by Izykowski et al (1998) to deal with the inaccuracy of conventional phasor analysis. However, this compensator was still developed by steady-state phasor computations, which may not ensure its performance under different fault inception angle conditions.…”

Accurate fault location algorithm for double-circuit series compensated lines using a limited number of two-end synchronized measurements

“…The adopted model of these instrument transformers along with their parameters are given in Fig. 7a and b [19,20].…”