Device and method for restraining extra-high-voltage main transformer no-load closing electromagnetic transient problems

Abstract

The invention provides a device and a method for restraining extra-high-voltage main transformer no-load closing electromagnetic transient problems. The device comprises a transformer circuit breaker and a control module, the transformer circuit breaker comprises a main contact, a closing resistor and an auxiliary contact, the auxiliary contact is serially connected with the closing resistor and then parallelly connected with the main contact, the value of resistance of the closing resistor is determined according to resonant overvoltage, excitation inrush current, voltage sag, energy consumption of the closing resistor within a preset range when a no-load main transformer is closed, the control module controls the auxiliary contact to connect when the transformer circuit breaker is closed, so that the closing resistor is serially connected into a loop, and the control module controls the main contact of the transformer circuit breaker to close after a preset period of time, so that the closing resistor is short-circuited. The value of resistance of the closing resistor in the transformer circuit breaker is selected in terms of the resonant overvoltage, the excitation inrush current, the voltage sag and the energy consumption of the closing resistor, and closing and space-variant requirements of a transformer in an extra-high-voltage power transmission system are met.

Description

technical field [0001] The invention relates to the technical field of UHV power transmission equipment, in particular to a device and method for suppressing the electromagnetic transient problem of no-load closing of UHV main transformers. Background technique [0002] First introduce the voltage sag: [0003] Voltage sag is also known as voltage sag, voltage sag or voltage drop. According to the definition of the International Institute of Electrical and Electronics Engineers (IEEE), it refers to the reduction of the root mean square value (effective value) of the voltage to 0.1 to 0.9 times under power frequency conditions. The phenomenon of short-term voltage fluctuations between rated voltages with a duration of 10ms (based on the power frequency of 50Hz in my country, a cycle is 20ms) to 1min. The amplitude, duration and phase jump of the voltage sag are the three most important characteristic quantities of the nominal voltage sag. In the field of UHV, high-amplitude ...

AI Technical Summary

Problems solved by technology

In the field of UHV, high-amplitude and slow-decay resonant overvoltage and excitation inrush current may occur when the main transformer is switched on without load, and may cause electromagnetic transient problems such as large-scale and long-term voltage sags. High-amplitude overvoltage The voltage is detrimental to the insulation safety of UHV equipment, and may cause the overvoltage protection action of UHV system,

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