PT intelligent resonance elimination device for power distribution network

Abstract

The invention discloses a PT intelligent resonance elimination device for a power distribution network. The PT intelligent resonance elimination device comprises a signal conditioning module, a data collecting module, a central processing unit, a sound-light alarming module, a resonance elimination device triggering module and a resonance elimination device body. The signal conditioning module collects a voltage signal and carries out lowpass filtering on the signal to eliminate the frequency aliasing phenomenon possibly caused by a signal with over-high frequency during spectral analysis; the data collecting module carries out A / D conversion on the voltage signal processed by the signal conditioning module; the central processing unit carries out data analysis on the voltage signal and sends the signal to the sound-light alarming module and the resonance elimination device triggering module; the sound-light alarming module can give out a sound-light alarm when a system has faults; the resonance elimination device triggering module sends out a trigger signal to control switching on and off of a thyristor of the resonance elimination device body; the resonance elimination device body comprises a damper electric reactor and an antiparallel silicon-controlled thyristor. By means of the PT intelligent resonance elimination device for the power distribution network, the ferromagnetic resonance fault can be effectively eliminated, a single-phase grounding fault and the ferromagnetic resonance fault can be effectively distinguished, and the sound-light alarm is given out.

Description

technical field [0001] The invention belongs to the field of power system safety analysis and relates to a PT intelligent harmonic elimination device for a distribution network. Background technique [0002] In the distribution network of 6 ~ 35KV, the neutral point of the system is generally not grounded. The system bus is connected with an electromagnetic voltage transformer (PT) for measuring and monitoring the insulation to the ground. When the bus switch closes, the single-phase arc of the line disappears automatically, or the system load changes drastically, the temporary The state impact process may excite the ferromagnetic resonance phenomenon between the PT and the capacitance of the three-phase wires to the ground, resulting in system overvoltage and overcurrent in the PT, causing flashover to the ground of the weakly insulated equipment in the system, and blowing of the high voltage fuse of the PT , and even burned PT. The ferromagnetic resonance of PT is an int...

AI Technical Summary

Problems solved by technology

[0004] 1. The PT open delta connection damping resistance, the disadvantage is that when selecting the resistance, if the resistance is too large, the harmonic elimination effect will not be achieved, if the resistance is too small, the PT is required to have a large enough heat capacity;

[0005] 2. A non-linear resistance resonance eliminator is connected in series between the neutral point of the primary side of the PT and the ground. Its limitation is that it is only valid for this PT and not valid for other PTs. Therefore, a non-linear resistance must be installed for each PT. Harmonic eliminator, and the volt-ampere characteristics of PT itself are inconsistent, which affects the signal action of the system insulation monitoring device;

[0006] 3. Using the 4PT wiring method, the disadvantage is that there may be a large circulation in the open triangle, which will cause the primary winding and the remaining winding to overheat

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