Method for inhibiting power frequency voltage from being raised after switch-on of ultrahigh and extra-high voltage no-load line

Abstract

The invention belongs to the field of an electronic device of an electric system and particularly relates to a method for inhibiting a power frequency voltage from being raised after switch-on of an ultrahigh and extra-high voltage no-load line. The invention discloses the method for inhibiting the power frequency voltage from being raised after the no-load line is switched on by adopting a high-capacity controllable high resistance. In the method, before the no-load line is switched on, the capacity of the high-capacity controllable high resistance is regulated to a large value; and after the line is switched on, the line does not provide a capacitive reactive power so as to inhibit the power frequency voltages of a transformer substation and the line. The invention provides the method for inhibiting the power frequency voltage from being raised after the ultrahigh and extra-high voltage no-load line is switched on by adopting a high-capacity controllable reactor, wherein the maximum capacity of the controllable reactor exceeds the capacity provided by a positive-sequence capacitor of the line. Before the line is switched on, the high-capacity controllable reactor is regulated to have the maximum capacity; and after the line is switched on, the reactor carries out overcompensation on the ultrahigh and extra-high voltage line so as to meet the requirement on inhibition on the power frequency voltages of the transformer substation and the line.

Description

technical field [0001] The invention belongs to the field of electric power system electronic devices, and in particular relates to a method for suppressing the rise of power frequency voltage after super- and extra-high voltage no-load lines are switched on. Background technique [0002] Due to the long-distance power transmission requirements such as west-to-east power transmission and north-south mutual power supply in my country, most UHV lines and 750kV EHV lines are relatively long, and the capacitive reactive power on the lines is very large. After the no-load line is closed, The power frequency voltage of substations and lines has increased significantly, even exceeding the highest operating requirements of the system, which has a great impact on the normal operation of the system and the safe operation of substation equipment and lines. At present, it is generally used to install fixed controllable reactors on the line to compensate the capacitive reactive power of t...

AI Technical Summary

Problems solved by technology

In order to meet the requirements of line transmission power and avoid resonance, the capacity of the controllable reactor should not be too large. At present, the compensation degree of the controllable reactor on the ultra-high voltage and ultra-high voltage lines to the positive sequence capacitance of the line is generally 60-90%. After closing, the line still provides capacitive reactive power to the system, and the power frequency voltage of the substation busbar and line will still rise, even exceeding the maximum operating voltage requirement of the system

Therefore, it is also necessary to control the busbar voltage of the substation before closing. Due to the limitations of system transmission power and reactive power debugging methods, it is often difficult to control the busbar voltage of the substation before closing.

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