A Coordinated Control Method for Improving Hybrid Back-to-Back DC Systems

A coordinated control and DC system technology, applied in the field of power transmission and distribution, can solve the problems of lack of technical solutions for flexible DC coordinated control, flexible DC without communication exchange, etc., to improve the ability to cross AC faults, ensure safe and stable operation, reduce The effect on the probability of commutation failure

Active Publication Date: 2018-07-06
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the hybrid double-infeed DC transmission system in the prior art is similar to the hybrid back-to-back DC system. Electrical distance, there is no communication exchange between flexible DC and conventional DC
Therefore, the existing technology lacks a technical solution for coordinated control between flexible DC and conventional DC

Method used

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  • A Coordinated Control Method for Improving Hybrid Back-to-Back DC Systems
  • A Coordinated Control Method for Improving Hybrid Back-to-Back DC Systems

Examples

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Effect test

Embodiment

[0027] The invention provides a coordinated control method for improving the capability of resisting commutation failure and fault ride-through capability of a hybrid back-to-back DC system. The control method is configured in an inverter station of a hybrid back-to-back DC system.

[0028] In one embodiment, a schematic structural diagram of a hybrid back-to-back DC system in which flexible DC units and conventional DC units operate in parallel is shown in figure 1 shown. The hybrid back-to-back DC system consists of a conventional DC unit and a flexible DC unit. The two DC units are in the same converter station and share the same AC bus.

[0029] The rectifier side of the conventional DC unit adopts constant active power control or constant DC current control, and the inverter side adopts constant DC voltage or constant turn-off angle control; the flexible DC unit adopts the direct current vector control method based on dq axis decoupling, which can be It is divided into ...

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Abstract

The invention discloses a coordinated control method for improving a hybrid back-to-back DC system. The method is used for an inverter station of a hybrid back-to-back DC system in which a flexible DC unit and a conventional DC unit operate in parallel. The method includes the following steps: Step 1. In the flexible DC unit The reactive power outer loop controller of the unit and the AC voltage outer loop controller are additionally switched off angle coordination controller; step 2, according to the judgment result of the fault judgment module, the control mode of the flexible DC unit reactive power outer loop control is selected as reactive power A power outer loop controller or an AC voltage outer loop controller; Step 3. Determine the limit of the reactive current reference value and the active current reference value of the current inner loop control of the flexible DC unit according to the judgment result of the fault judgment module. The invention can effectively reduce the probability of phase commutation failure in the hybrid back-to-back DC system, and improve the ability of the system to ride through AC faults.

Description

technical field [0001] The invention relates to the technical field of power transmission and distribution, in particular to a coordinated control method for improving the commutation failure resistance capability and fault ride-through capability of a hybrid back-to-back DC system. Background technique [0002] The traditional current-source grid commutated HVDC (Line Commutated Converter High Voltage Direct Current, LCC-HVDC) has been widely used in my country, and has the characteristics of large transmission power and long transmission distance, but there is a risk of commutation failure. Consumption of a large amount of reactive power and other limitations [1] . In recent years, the Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) based on full-control devices has developed rapidly, with independent decoupling control of active and reactive power and continuously adjustable reactive power. However, there are also problems such as high cost and rela...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/36H02J3/18H02J3/12
CPCY02E40/30Y02E60/60
Inventor 王振赵成勇蒋碧松郭春义李晋伟陈欢国建宝黄义隆
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID
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