Variable frequency transformer fault ride-through control method and circuit

A transformer fault and control method technology, which is applied in the direction of controlling generators, controlling electromechanical brakes, controlling electromechanical transmissions, etc., can solve problems such as fluctuations and high cost of fault ride-through circuits

Active Publication Date: 2020-07-31
GUANGDONG POWER GRID CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The interaction between the three-phase unbalanced voltage and current will cause the electromagnetic torque, active power and reactive power of the variable frequency transformer to produce twice the electrical angular velocity of the rotor rotation, twice the synchronous angular velocity of the stator and twice the synchronous angular velocity of the rotor. fluctuation
However, a parallel three-phase converter is required to provide a stable power supply, resulting in high cost of the fault ride-through circuit

Method used

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  • Variable frequency transformer fault ride-through control method and circuit
  • Variable frequency transformer fault ride-through control method and circuit
  • Variable frequency transformer fault ride-through control method and circuit

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Embodiment 1

[0072] The purpose of this application is to provide a variable frequency transformer fault ride-through circuit without a parallel three-phase converter, and propose a fault ride-through control method to achieve "use the left series three-phase converter to solve the unbalance problem on the left, and use the right The series three-phase converter solves the unbalance problem on the right”, and can maintain the stability of the DC bus voltage and maintain the control ability of reactive power without parallel three-phase converters.

[0073] The specific idea is: by controlling the output voltage of the three-phase converter connected in series on the stator side, the following effects can be achieved: (1) maintaining the stability of the DC bus voltage; (2) maintaining the ability to control reactive power; (3) suppressing the negative sequence voltage of the stator .

[0074] The negative sequence voltage of the rotor is suppressed by controlling the output voltage of the ...

Embodiment 2

[0109] This embodiment provides a variable frequency transformer fault ride-through circuit, such as Figure 5 As shown, it includes: stator-side power grid 1, stator-side series three-phase transformer 31, stator-side series three-phase converter 41, control circuit, H-bridge converter 6, rotor-side series three-phase converter 42, rotor-side series three-phase Transformer 32, rotor side grid 2;

[0110] The stator side grid 1 is connected to one end of the AC output end of the stator side series three-phase transformer 31;

[0111] The other end of the AC output end of the three-phase series transformer 31 on the stator side is connected to the stator winding of the variable frequency transformer 9;

[0112] The AC input terminal of the stator-side three-phase series transformer 31 is connected to the AC terminal of the stator-side series three-phase converter 41;

[0113] The rotor side grid 2 is connected to one end of the AC output end of the rotor side series three-pha...

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Abstract

The invention relates to a variable-frequency transformer fault ride-through control method and circuit. According to the method, by controlling the output voltage of a stator side series three-phaseconverter, the method has the effects of (1) maintaining the stability of a DC bus voltage, (2) maintaining the control capability of reactive power and (3) suppressing the negative sequence voltage of a stator; and the negative sequence voltage of a rotor is suppressed by controlling the output voltage of a rotor side series three-phase converter. Compared with the technical scheme that a parallel three-phase converter and a series three-phase converter are adopted, the method of the invention has the following characteristics that no equipment is additionally arranged, the stator voltage andthe rotor voltage are controllable, and fluctuation of electromagnetic torque, active power and reactive power is thoroughly restrained. Compared with the technical scheme that two parallel three-phase converters and two series three-phase converters are adopted, the method of the invention has the following characteristics that fault ride-through control over the variable-frequency transformer can be achieved without connecting the three-phase converters in parallel, the number of the three-phase converters of the fault ride-through circuit is reduced to two from four, and the system cost isgreatly reduced.

Description

technical field [0001] The invention relates to the technical field of power grid asynchronous interconnection, and more specifically, to a variable frequency transformer fault ride-through control method and circuit. Background technique [0002] With the increasing use of unbalanced loads in power systems, the possibility of voltage unbalance phenomena occurring in transmission lines increases gradually. The stator winding and rotor winding of the variable frequency transformer are respectively connected to two sets of transmission lines, so the grid voltage on both sides of the variable frequency transformer will be unbalanced. [0003] When a three-phase voltage imbalance fault occurs on both sides of the variable frequency transformer, the current flowing through the variable frequency transformer will be unbalanced in three phases. The interaction between the three-phase unbalanced voltage and current will cause the electromagnetic torque, active power and reactive po...

Claims

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Application Information

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IPC IPC(8): H02J3/26H02J3/12H02J3/24H02P21/00H02P21/28H02P21/26
CPCH02J3/12H02J3/24H02J3/26H02P21/0003H02P21/26H02P21/28Y02E40/50
Inventor 卢嘉豪
Owner GUANGDONG POWER GRID CO LTD
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