Overvoltages Due to Open-Phase Occurrence in Reactor Compensated EHV Lines

Determining optimal neutral reactor to limit overvoltages and duration of secondary arc of transmission lines

“…where F N and F D are function of X N and other known parameters and are given in Appendix A2. According to (11), the amplitude of the induced voltage in the isolated phase comprises two parts: the first one mainly depends on the system voltage (V A ), and the second depends on the initial shunt rector current…”

“…On the other hand, during the SPO condition, it can be shown that VAN = VIN − VN . Since V N and V IN have already obtained in (10) and (11), respectively, Ф A is known. Ultimately, by applying the inverse Laplace transform to Ф A, the shunt reactor flux, first constraint of (1), in the time domain is obtained…”

“…However, the overvoltage issue is not considered. Some research works have analytically studied the possibility of resonant overvoltages appearing under the open-phase condition [11].The series resonance phenomenon is considered by calculating an equivalent shunt compensated transmission line circuit as one or two phases are left open [11]. However, the magnetic coupling between phases of the shunt reactor is not taken into account, which might have a significant effect on overvoltage on the isolated phases.…”

“…It is demonstrated that the addition of a neutral reactor in the neutral point shifts the resonant point by compensating the interphase capacitance and assistances to curb the induced voltages [12][13][14]. In [15], further investigations have been performed to analyse the impact of the neutral reactor and different TL design parameters on the resonant point based on the formula presented in [11]. Most studies only used the phasor domain approach to analyse and model the system for obtaining the neutral reactor, considering the steady-state conditions [11,[16][17][18].…”

“…In [15], further investigations have been performed to analyse the impact of the neutral reactor and different TL design parameters on the resonant point based on the formula presented in [11]. Most studies only used the phasor domain approach to analyse and model the system for obtaining the neutral reactor, considering the steady-state conditions [11,[16][17][18]. In [18], the effects of shunt compensation, neutral reactor, and system frequency have been analysed on open-phase overvoltage, but it merely considered steadystate conditions.…”