Primary and secondary combined resonance elimination device

Abstract

The invention discloses a primary and secondary combined resonance elimination device. Most of the power systems in China adopt a neutral point ineffective grounding mode; damage to electrical equipment and large-area power failure accidents are easily caused by the common non-linear resonance of the grounding mode. The device for eliminating the resonance by combining primary resonance elimination and secondary resonance elimination comprises a core control unit, a signal acquisition unit, a primary resonance elimination unit and a secondary resonance elimination unit. When a system is resonant, the core control unit firstly controls the secondary resonance elimination unit to operate; after the resonance elimination operation is finished, the core control unit scans the signal acquisition unit to detect whether the resonance is completely eliminated; if the resonance cannot be completely eliminated within certain time, the primary resonance elimination unit is started, namely a pressure limiter is used for eliminating the residual resonance energy. Due to the functional structure, the rationality, the thoroughness and the safety of the resonance elimination can be improved.

Description

technical field [0001] A harmonic elimination device combining primary and secondary, which involves the technology of eliminating the resonance generated by the non-effective grounding of the neutral point in the power system. Carrying out a harmonic elimination is a harmonic elimination device in which the two harmonic elimination methods complement each other. Background technique [0002] Most of the power systems in our country adopt the neutral point ineffective grounding method, which has high power supply reliability, but nonlinear resonance is relatively common, which not only has a high amplitude, but also has a large energy, and can spread throughout the entire power grid, destroy Once it happens, it often causes damage to electrical equipment and large-scale power outages. [0003] At present, there are two most commonly used methods to eliminate resonance: one is secondary resonance elimination, that is, short-circuiting the secondary opening winding of the vo...

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Problems solved by technology

[0002]Most of the power systems in my country adopt the neutral point ineffective grounding method, which has high power supply reliability, but nonlinear resonance is common, which not only The value is high, and the energy is large, and it can spread throughout the entire power grid, which is very destructive. Once it occurs, it often causes damage to electrical equipment and large-scale power outages

[0003]At present, there are two most commonly used methods to eliminate resonance: one is secondary resonance elimination, that is, short-circuiting the secondary open winding of the voltage transformer for a short time, by consuming resonance Energy, so that the resonance intensity gradually attenuates and disappears. This method is simple, but sometimes it is difficult to completely eliminate the resonance. If the resonance of the system is a low-frequency resonance, it is more difficult to eliminate the resonance; A resistance (linear or non-linear resistance) is connected in series between the neutral point and the ground. The purpose is to increase the reactance of the zero-sequence return and damp the zero-sequence current. Although this method can protect the voltage transformer, it will affect the measurement accuracy of the voltage transformer. In addition, when a single-phase ground fault occurs in the system, the resonance eliminator often burns itself due to its limited capacity, especially when the resonant current generated by the system is large, a high voltage will be generated on the resonance eliminator , poses a threat to the insulation of the neutral point of the voltage transformer

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