Front acceleration protection method for direct-current power distribution network

A DC distribution network, front acceleration technology, applied in the direction of measuring current/voltage, emergency protection circuit devices, electrical components, etc., can solve problems such as reducing fault removal time, achieve perfect line protection, improve quickness, and increase options sexual effect

Active Publication Date: 2020-06-19
XIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a front-acceleration protection method for DC distribution network, which solves the requirement of the existing DC distribution network on the quickness of protection, and can effectively increase the speed of fault removal, thereby reducing the fault removal time

Method used

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  • Front acceleration protection method for direct-current power distribution network
  • Front acceleration protection method for direct-current power distribution network
  • Front acceleration protection method for direct-current power distribution network

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Embodiment 1

[0058] Built in MATLAB / SIMULINK such as Figure 5 The topological structure model of the four-terminal ring network DC power distribution system is shown. The model is constructed by four MMC converters, connected to four lines, and a pre-acceleration protection device is installed on the source side of each line, respectively AR12, AR21, and AR13 , AR31, AR24, AR42, AR34, AR43, each front acceleration protection device has a corresponding DC circuit breaker, the installed DC circuit breaker is the current mainstream hybrid DC circuit breaker, its structure diagram is as follows Figure 6 The length of the DC distribution line shown is 100km, and the DC voltage U of the system is dc It is ±100kV, and the sampling frequency is 10kHz. The relevant parameters of the ring network distribution network are shown in Table 1.

[0059] Table 1 Parameter table of four-port DC distribution network

[0060]

[0061]

[0062] Assuming that the first start-up criterion such as formu...

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Abstract

The invention discloses a front acceleration protection method for a direct-current power distribution network, and belongs to the technical field of the relay protection of the direct-current power distribution network. In order to solve the problem of quick action of protection, the pre-acceleration thought is introduced, the instantaneous values of positive and negative currents are compared with the maximum load current, and the instantaneous values of the positive and negative voltages are compared with the bus voltage to carry out a first starting criterion; a second starting criterion is performed by utilizing the average value of the current and the voltage and the fault current and the fault voltage of a single-pole grounding high-resistance fault; a front acceleration protectiondevice issues a tripping instruction to a direct-current circuit breaker; at the moment, the characteristics of internal faults and external faults are utilized; the maloperation of a circuit breakerwith an external fault is recovered to be normal; the reclosure is started at the moment after 150 ms of dissociation delay of a switched-off direct-current circuit breaker, the fault disappears and the system returns to normal if the fault is an instantaneous fault, the direct-current circuit breaker is switched off again to remove the fault if the fault is a permanent fault at the moment, and the front acceleration protection scheme is favorable for perfecting the line protection of the direct-current power distribution engineering.

Description

technical field [0001] The invention belongs to the technical field of relay protection for DC distribution networks, and relates to a front acceleration protection method for DC distribution networks. Background technique [0002] The society pays more and more attention to the problem of environmental pollution, and the policy encourages the market to invest heavily in the development of clean energy, gradually promoting the formation of a new energy pattern with the power network as the main core carrier. The rapid development of DC-type clean energy such as photovoltaics and direct-drive fans, and DC-type loads such as electric vehicles, data centers, and smart buildings has led to the continuous deepening of the "source and load" of the distribution network. The urban load density increases linearly with the acceleration of urbanization, and the traditional AC distribution network can no longer meet the demand of urban load. The DC distribution network can effectively ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/26G01R31/08G01R19/165
CPCH02H7/268G01R31/085G01R19/16538
Inventor 段建东杜晓通李再男
Owner XIAN UNIV OF TECH
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