MCC single-phase grounding PC override trip solving method for low-voltage auxiliary power
A single-phase grounding, leapfrog tripping technology, applied in electrical components, circuit devices, emergency protection circuit devices, etc., can solve the problem of not setting single-phase grounding protection, and achieve the effect of avoiding unplanned shutdowns
Inactive Publication Date: 2021-04-02
华能青岛热电有限公司
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Problems solved by technology
[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art, provide a solution to the single-phase grounding PC overstep trip of the low-voltage utility power MCC, and solve the problem that there is no separate single-phase grounding protection at present
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[0015] The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.
[0016] like figure 1 As shown, a low-voltage utility power MCC single-phase ground PC leapfrog tripping solution includes the following steps:
[0017] Step 1. Embed and install the phase-to-ground short circuit protection device on the side cable room door of the MNS drawer cabinet;
[0018] Step 2. Install the miniature zero-sequence current transformer on the beam of the cable room behind the cabinet, and the beam can hold more than six miniature zero-sequence current transformers;
[0019] Step 3. The sampling signal of the phase-to-ground short-circuit protection device is connected to the miniature zero-sequence current transformer. The wiring method of the m...
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The invention discloses an MCC single-phase grounding PC override trip solving method for low-voltage auxiliary power, and particularly relates to the technical field of electrical line protection. The method comprises the following steps: step 1, enabling a phase-to-ground short-circuit protection device to be embedded into a side cable chamber door plate of an MNS drawer cabinet; and step 2, installing a miniature zero-sequence current transformer on the cross beam of the cable chamber behind the cabinet. According to the MCC single-phase grounding PC override trip solving method for low-voltage auxiliary power, the problem of MCC feeder single-phase grounding and incoming line override trip when MCC incoming lines have zero-sequence protection is solved, the problem that when the MCC incoming lines have no zero-sequence protection, MCC feeder single-phase grounding and two-stage switch refusal cause consecutive ignition of grounding feeder fault points is solved, unplanned shutdowncaused by single-phase earth fault override trip is effectively avoided, contributions are made to safe and stable operation of the system, and the problem that no single-phase earth protection is setat present is solved.
Description
technical field [0001] The invention relates to the technical field of electric circuit protection, in particular to a solution to a single-phase-grounded PC overstep trip of a low-voltage utility power MCC. Background technique [0002] The MCC feeder protection of low-voltage utility power is realized by SL two-stage thermal magnetic plastic case switch to realize phase-to-phase short-circuit, overload and zero-sequence protection. This is the basic configuration of most coal-fired power plants. There is no separate single-phase grounding protection, but Phase-to-phase short-circuit protection is also used as grounding protection. After a single-phase ground fault occurs during operation, due to the long line, the sensitivity of phase-to-phase short-circuit protection is not enough (or the non-metallic ground fault current is small), resulting in zero-sequence protection of MCC incoming line (PC feeder) Leapfrog tripping, in severe cases, will bypass the low-voltage substa...
Claims
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Login to View More IPC IPC(8): H02H7/26H02H3/34
CPCH02H7/26H02H3/34
Inventor 王冠旻周鹏林林兆乐邵华波
Owner 华能青岛热电有限公司