Investigation of performance of ferroresonance suppressing circuits in coupling capacitor voltage transformers

Abstract

In order to restrain ferroresonance in coupling capacitor voltage transformers (CCVT), three kinds of ferroresonance suppression circuits (FSCs): the resonant type, the fast-saturation reactor type and electronic type which are connected to secondary side of CCVTs, are proposed in this paper. Frequency domain analyses, for voltage ratio magnitude, are carried out for CCVTs to obtain preferable FSC. Furthermore, using surge suppressors such as metal oxide varistors (MOV) to improve the performance of the FSCs is investigated. Time domain simulations demonstrate that ferroresonance can be cleared in few cycles in presence of FSCs. The Electromagnetic Transients Program (EMTP) is used for modeling and fine-tuning the FSCs.

Estimation of Electronic Suppression Circuit Resistance for Protective Relaying Applications

“…Figure 11 also shows the TSTR of an electronic CVT with R TE = 45 , which is obtained by a trial-and-error method [20][21][22]. The low ratio obtained using R est = 15 indicates that the primary information will be available to the relay relatively faster than the one with R TE = 45 .…”

“…The electronic FSC considered here is resistance (R) in series with power electronic device [21,22], the damping resistance value of which is to be estimated. Figure 1 shows the detailed model of the CVT used to estimate the damping resistance(R est ), where SW 1 and SW 2 is the switch, C 1 and C 2 are the stack capacitance, R C and L C are the tuning inductor resistance and inductance, C T is the equivalent stray capacitance of primary winding, R T 1 , R T 2 , and R B are the primary and secondary winding resistance and relay burden, L T 1 and L T 2 are the primary and secondary winding inductance, R T C is the core loss resistance, and L T C is the magnetizing inductance.…”

“…In addition to this, a CVT with an electronic FSC has been recently introduced in the literature [20][21][22], where the FSC is made up of a power electronic device in series with resis- tance to improve the transient response of the CVT; however, a trial-and-error method was adopted in [20][21][22] to estimate the damping resistance. Even though the authors of [21,22] adopted a ferro-resonance test (FT) as per [23], testing is done only at the rated primary voltage of the CVT, i.e., at 400 kV, whereas [23] demanded for testing to be done at four different voltage levels, i.e., 0.8, 1, 1.2, and 1.5 times the rated voltage.…”

“…Even though the authors of [21,22] adopted a ferro-resonance test (FT) as per [23], testing is done only at the rated primary voltage of the CVT, i.e., at 400 kV, whereas [23] demanded for testing to be done at four different voltage levels, i.e., 0.8, 1, 1.2, and 1.5 times the rated voltage.…”

Effect of Metal Oxide Arrester on Chaotic Behavior of Power Transformers

“…[15]. Ferro resonance in capacitive voltage transformer using nonlinear models along with (Current/Voltage) limiting filters has been discussed in Refs [16][17][18][19]. Evaluation of chaos in voltage transformer, effect of resistance key on the chaotic behavior voltage transformer and and subharmonics that produced with ferroresonance in this type transformer are studied in Refs.…”