Improved capacitive MMC topological structure with direct-current fault self-clearing capability

A technology of DC fault and topology structure, applied in the direction of converting AC power input to DC power output, electrical components, power transmission AC network, etc., can solve problems such as endangering the safe operation of the system, blocking fault current, etc., and achieve rapid removal of positive and negative DC fault and the effect of reducing the cost of the converter

Inactive Publication Date: 2021-02-09
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, after the DC fault of the traditional half-bridge sub-module MMC, due to the freewheeling effect of the diode, the system approximately has a three-phase short circuit, and cannot rely on itself to quickly realize the DC fault self-clearing, and cannot block the drive signal of the converter Fault current, seriously endangering the safe operation of the system

Method used

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  • Improved capacitive MMC topological structure with direct-current fault self-clearing capability
  • Improved capacitive MMC topological structure with direct-current fault self-clearing capability
  • Improved capacitive MMC topological structure with direct-current fault self-clearing capability

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Embodiment 1

[0046] This embodiment is used to verify the DC fault self-blocking capability of the improved capacitive MMC topology with DC fault self-clearing capability

[0047] A hybrid MMC double-terminal DC transmission system is built in PSCAD. The DC side of the MMC adopts constant DC voltage control to maintain the stability of the DC voltage. The relevant parameters of the model are shown in Table 4. The traditional sorting method can ensure the balance of the capacitor voltage, and the modulation strategy is the nearest level approximation modulation. A permanent interpolar short-circuit fault occurs 1 second after the system runs stably. The fault detection time is 0.001s, and all sub-modules in the MMC will be locked in 1.001s.

[0048] Table 1 System parameters

[0049]

[0050] refer to Figure 6-9 , the hybrid MMC fault self-clearing simulation results using ICSM and HBSM are as follows Figure 6-9 shown. A fault occurs 1 second after the system stabilizes. Before the...

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Abstract

The invention relates to the technical field of direct-current power transmission, and discloses an improved capacitive MMC topological structure with direct-current fault self-clearing capability. The structure comprises a plurality of bridge arms, and each bridge arm comprises a half-bridge unit, and each half-bridge unit comprises a half-bridge unit, an insulated gate bipolar transistor, a diode and a clamping capacitor which are in anti-parallel connection with the insulated gate bipolar transistor. By means of capacitor clamping and reverse cut-off characteristics of a diode, the improvedcapacitive MMC topology with the direct-current fault self-clearing capacity has the direct-current fault clearing capacity and has the advantages of being economical and capable of rapidly clearingforward and reverse direct-current faults.

Description

technical field [0001] The invention relates to the technical field of direct current transmission, in particular to an improved capacitive MMC topology structure with direct current fault self-clearing capability. Background technique [0002] The high-voltage direct current transmission technology based on voltage source converter is a new type of power transmission technology based on voltage source converter, self-shutdown device and pulse width modulation (PWM) technology. , There will be no commutation failure, no communication between converter stations, and easy to form a multi-terminal DC system. As a new generation of DC transmission technology, flexible DC transmission is similar in structure to HVDC, and is still composed of a converter station and a DC transmission line (usually a DC cable). Different from the current source converter type high-voltage DC transmission based on phase-controlled commutation technology, the converter in the flexible DC transmissio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/5387H02M1/32H02J3/36
CPCH02J3/36H02M1/32H02M7/53871Y02E60/60
Inventor 王渝红叶葳罗雍溢闵杨晰
Owner SICHUAN UNIV
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