Title: Controllable gap for protecting transformer neutral point
Application Number: 200610127980 Application Date: 2006.09.06
Publication Number: 1933268 Publication Date: 2007.03.21
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02H7/04
Applicant(s) Name: China Electric Science Inst. Address:
Inventor(s) Name:
Attorney & Agent: guohe
Abstract:
    This invention relates to a control gap used in protecting neutral points of transformers including a fixed gap, a control gap and its control loop and a capacitance equalizing loop, in which, the fixed gap is serial to the control gap, one end of the fixed gap is connected to the neutral point and one end of the control gap is connected to the earth, the control gap is controlled by the control loop to trigger actions, the capacitance equalizing loop is parallel at both ends of the fixed gap and control gap for bleeding, the equalizing capacitor parallel to the control gap is composed of a serial equalizing capacitor with small capacitance value and high voltage endurance and a measuring capacitor with great capacitance and low voltage endurance providing input signals for the control loop. This invention jointly uses an arrester often used for transformer neutral point to protect the neutral point including: impacted by thunder and operation, the arrester operates to limit over voltage of the neutral point, when the point insulated line-frequency over voltage is threatened in the system, the control gap breaks through it to discharge to protect the insulation of the point and the arrester.
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