Investigation of the circuit breaker reignition overvoltages caused by no‐load transformer switching surges

Abstract

When an unloaded transformer or motor is switched under certain conditions, the circuit breaker can be exposed to a re-strike effect that leads to voltage escalation. The effect of reignition depends not only on the Qpe of circuit breaker, but also on the surrounding network.In this paper we describe a detailed model of all system components, which is extended where necessary, for the calculation of transients caused by the vacuum circuit breaker switching surges. Especially the transformer modelling is explained in detail for n broad frequency range because of a very complex transient behaviour. The system confguration consisting of a circuit breaker, a cable, a transformer and arresters is observed and modelled by means of some provided measured data. The results of some models are compared with measurements. The models have been imbedded into the Alternative Transient Program (ATP). The program developed here can be widely used for studies of transient recover?, overvoltages caused by interruption of transformer steady-state and inrush currents i f the measured data and parameters for the system components are known.

Modeling and Mitigation for High Frequency Switching Transients Due to Energization in Offshore Wind Farms

“…When the transient recovery voltage (TRV) exceeds the DS, prestrikes occur. The recovery of DS is modeled based on Equation (1) provided by [19]. It shows a linear relationship between the value of DS (U dw ) and the time (t):…”

Analysis of Very Fast Transients in Layer-Type Transformer Windings

“…The losses were calculated from the inductance matrix and the capacitance matrix [12]. The impedance and admittance matrices and are then (14) In (14), the second term in the first equation corresponds to the Joule losses taking into account the skin effect in the copper conductor and the proximity effect. The second term in the second equation represents the dielectric losses.…”

“…The second term in the second equation represents the dielectric losses. In (14), is the distance between layers; is the conductor conductivity; and is the loss tangent of the insulation.…”

“…Multiple reignitions can occur during the switching of transformers and motors with vacuum CBs (VCBs), because of the ability of VCBs to interrupt high-frequency currents. The development process of multiple reignitions has been traced in detail [14], [15]. It has been shown that the problem is not caused by the VCB or the transformer, but by an interaction of both [10].…”

Wideband Transformer Modeling Including Core Nonlinear Effects

“…However, this alternative model is still limited as it is not capable of taking into account core non-linear effects [13]. It is known that the non-linear B-H characteristics of the steel results in a shift in frequency and magnitude of the impedance frequency responses up to several tens of kHz, depending on the transformer terminal conditions [14], [15]. These changes in frequency response characteristics may substantially impact the conditions prior to a fast transient event, e.g.…”