Electric network deharmonic reactor

A reactor and power grid technology, applied in the direction of electrical components, circuit devices, emergency protection circuit devices for limiting overcurrent/overvoltage, etc., can solve the problem of not being able to correctly distinguish between fundamental frequency resonance and single-phase ground faults Completely insulated voltage transformers, large modification workload and other problems, to achieve the effect of simple structure, high reliability and cost economy

Inactive Publication Date: 2008-07-23
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But its obvious disadvantage is that it cannot correctly distinguish the fundamental frequency resonance and single-phase ground fault, because in these two cases, the voltage and waveform at both ends of the open delta winding are almost exactly the same
However, in the 35kV and 66kV distribution networks, since the three-phase PTs are semi-insulated voltage transformers, if the four-PT wiring method is used, then the three-phase PTs must be replaced with fully insulated voltage transformers, which will not only reduce the workload Large, and high investment cost; and for the voltage transformer installed indoors, due to the limitation of the volume of the switch cabinet, it is impossible to use a fully insulated voltage transformer
The application of four-PT connection mode in 35kV and 66kV systems has great limitations

Method used

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  • Electric network deharmonic reactor

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Embodiment 1

[0012] Embodiment 1: referring to accompanying drawing, AC is three-phase electromotive force, C 0 is the single-phase-to-ground capacitance of the power grid, and L is the inductance of the electromagnetic voltage transformer. A power grid harmonic elimination reactor, which consists of an inductance L 0 and a resistor R 0 It is connected in series between the neutral point of the 35kV or 66kV power grid and the ground; the inductance L 0 The value range is 6-65H in the 35kV grid, and 12-125H in the 66kV grid. The resistance R 0 The value range of is 5-20 times the inductance value, and the unit is Ω. Since the impedance design value of the harmonic elimination reactor is much smaller than the inductance of the voltage transformer, when the grid single-phase ground fault occurs, the existence of the harmonic elimination reactor is equivalent to adding a ground bypass to the PT, thereby effectively avoiding ferromagnetic resonance and The occurrence of PT high voltage fuse...

Embodiment 2

[0013] Example 2: See the accompanying drawings, in a 35kV grid, take the inductance L 0 The value is 20H, take the resistance R 0 The value is 300Ω.

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Abstract

This invention relates to a device for suppressing ferromagnetic resonance in a power net including: a reactor for eliminating resonance composed of an inductor and a resistor in serially connected between neutral points and the earth in 35kV or 66kV net, the sphere of the inductor is 6-65H in the 35kV net and 12-125H in the 66kV, the sphere of the resistor is 5-20 times of the inductance value.

Description

technical field [0001] The invention belongs to electric equipment, in particular to equipment for suppressing ferromagnetic resonance in a power grid. Background technique [0002] In 35kV, 66kV and below neutral point ungrounded power grids, electromagnetic voltage transformers (hereinafter referred to as PTs) are generally installed on the bus. When a single-phase ground fault occurs in the power grid, the voltage of the other two phases rises to the line voltage. Under the action of the line voltage, the PT core is oversaturated, and the ungrounded phase capacitance releases the charging charge through the PT, which easily causes ferromagnetic resonance. The overvoltage and overcurrent generated during resonance can burn out the high-voltage insurance in the slightest, and cause PT explosions and power outages in severe cases. [0003] Over the years, experts and scholars at home and abroad have done a lot of research on ferromagnetic resonance, and developed several ha...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H9/08
Inventor 谭伟璞杨以涵曲轶龙张健夏长根
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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