Coordination control method of multi-terminal flexible direct-current power transmission system

A DC transmission system and coordinated control technology, applied in electrical components, circuit devices, power transmission AC networks, etc., can solve problems such as reducing the reliability of multi-terminal flexible DC transmission systems, improve operating economy and flexibility, and maintain reliability. Operation, the effect of improving operational economy and flexibility

Active Publication Date: 2016-01-27
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The defect of its technical solution is that it depends on the high-speed communication between the upper control system and the converter station, which reduces the reliability of the multi-terminal flexible direct current transmission system

Method used

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  • Coordination control method of multi-terminal flexible direct-current power transmission system
  • Coordination control method of multi-terminal flexible direct-current power transmission system
  • Coordination control method of multi-terminal flexible direct-current power transmission system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] In Example 1, the upper-level control system communicates with the converter station normally.

[0040] Condition 1: When the power generated by the wind farm is small, the transmission power of the DC transmission system is in the interval [0, Pstate_0]. At this time, the converter station 1 is independently coordinated and controlled, and the upper control system corrects the droop control coefficient of the converter station , Making the slope of the active power-DC voltage characteristic curve larger and enhancing the power distribution characteristics of the system, such as Figure 4a Shown. Converter station 2 and converter station 3 are in the hot backup state, and the active power control reference value is set to 0; converter station 4 adopts constant active power control and is responsible for inputting the electric energy generated by the wind farm to the DC transmission system.

[0041] Condition 2: The power generated by the wind farm increases, and the transmis...

Embodiment 2

[0044] In embodiment 2, the upper-level control system fails to communicate with a certain converter station.

[0045] Before the fault occurs, the transmission power of the system is in the interval [Pstate_1, Pstate_2]. At this time, the converter stations 1 to 3 jointly participate in coordinated control. At a certain moment, the upper-level control system communicates with converter station 2 and the system transmission power is in the interval [Pstate_1, Pstate_2]. Converter stations 1 to 3 are still involved in coordinated control, and the droop control coefficient of converter station 2 remains current The value remains unchanged, and the droop control coefficients of converter station 1 and converter station 3 are calculated and set by the upper control system. In the case of a communication failure between the above-mentioned upper control system and a converter station, only the dynamic characteristics of the operation of the multi-terminal flexible DC transmission syst...

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PUM

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Abstract

The invention relates to a coordination control method of a multi-terminal flexible direct-current power transmission system. The multi-terminal flexible direct-current power transmission system comprises a coordination control convertor station, a hot spare control convertor station, and a power input convertor station. The coordination control convertor station employs an active power-direct-current voltage sag control way; the power input convertor station employs a fixed active power control way; and the hot spare control convertor station serves as a standby convertor station of the coordination control convertor station. An upper-level control system selects parts of or all hot spare control convertor stations to participate in coordination control according to the transmission power of the direct-current power transmission system and a sag coefficient is corrected in real time. According to the invention, flexibility and economy of the system operation can be improved on the premise that reliability of the multi-terminal flexible direct-current power transmission system is guaranteed.

Description

Technical field [0001] The invention relates to a control method of a multi-terminal flexible direct current transmission system. Background technique [0002] The multi-terminal flexible direct current transmission (MTDC) system consists of more than 3 voltage source converters (VSC) connected in series, parallel or hybrid. At present, parallel connection is usually used in actual projects. The AC side of the VSC is connected to the AC power grid, and the DC side is connected in parallel through the DC bus to form a DC network. Coordinated control is the basis for the multi-terminal flexible DC transmission system to maintain active power balance and DC voltage stability. The existing coordinated control strategies include single-point DC voltage control and multi-point DC voltage control. [0003] Single-point DC voltage control is also called master-slave control. The upper control system pre-sets the master converter station and slave converter station. The master converter ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/36H02J13/00
CPCY02E60/60
Inventor 李耀华罗永捷王平李子欣赵聪
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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