Comprehensive protection method and device of direct current collection cable

A DC cable and comprehensive protection technology, applied in emergency protection circuit devices, circuit devices, components of emergency protection devices, etc., can solve the problem of inability to accurately locate the fault location of DC cables and effectively protect power equipment.

Active Publication Date: 2018-04-20
YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST
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  • Abstract
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  • Application Information

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Problems solved by technology

[0005] This application provides a comprehensive protection and device for DC collection cables to solve the problems in the pri

Method used

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  • Comprehensive protection method and device of direct current collection cable
  • Comprehensive protection method and device of direct current collection cable
  • Comprehensive protection method and device of direct current collection cable

Examples

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Embodiment Construction

[0033] see figure 1 , which is a flow chart of a comprehensive protection method for a DC collection cable provided in this application. Such as figure 1 As shown, the method includes:

[0034] 101. Construct the DC capacitor discharge equivalent circuit at the beginning or end of the DC cable, and calculate the peak fault current and the time when the capacitor voltage drops to zero.

[0035] see figure 2 , which is a schematic diagram of connecting a current-limiting reactance in series between a converter and one end of a DC cable provided by this application. In the embodiment of this application, the typical topology of a two-level grid-connected converter used in a large-scale photovoltaic station is taken as an example. In this topology, the photovoltaic power station transmits electric energy through a DC After AC-DC conversion, it is merged into the AC main grid. Such as figure 2 As shown in the topology results, the neutral point of the DC side capacitor is d...

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PUM

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Abstract

The invention discloses a comprehensive protection method and device of a direct current collection cable, and relates to the technical field of fault protection of a direct current collection grid-connected system. The method can inhibit the fault current and accurately position the direct current cable fault position. The method mainly comprises the steps that a direct current capacitor discharging equivalent circuit of the starting end or terminal end of the direct current cable is built, wherein the equivalent circuit comprises series connection current limiting reactors used by the method; according to the capacitor discharging equivalent circuit and protection constraint conditions, the reactance parameter values of the current limiting reactors are calculated; the current limiting reactors with the reactance parameter values are connected in series in the direct current cable; the voltage values on the current limiting reactors connected in series in the direct current cable areobtained; according to the voltage values of the current limiting reactors, the fault types of the direct current cable are judged, wherein the fault types include a positive electrode fault, a negative electrode fault and an interelectrode fault; according to the fault types, the position of fault points is calculated and positioned. The method and the device are mainly applied to fault protection and fault positioning of the direct current cable in new energy source direct current collection networks and other direct current power transmission and power distribution networks.

Description

technical field [0001] The present application relates to the technical field of fault protection of a DC collection grid-connected system, in particular to a comprehensive protection method and device for a DC collection cable. Background technique [0002] Large-scale photovoltaic power plants are an effective way to use solar energy intensively on a large scale. However, with the continuous expansion of the scale of photovoltaic power plants, the harmonic resonance and reactive power transmission problems of traditional AC boost collection systems have become increasingly prominent, seriously affecting the safe operation and transmission capabilities of photovoltaic power plants. The replacement of AC by DC is an effective means to break the bottleneck of AC boost collection and AC access technology. The use of DC boost collection and transmission by photovoltaic power plants has become the current and future development direction. [0003] The photovoltaic power supply,...

Claims

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Application Information

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IPC IPC(8): G01R31/08H02H1/00H02H7/22H02H7/26
CPCG01R31/083H02H1/0007H02H7/226H02H7/268
Inventor 奚鑫泽李胜男邢超徐志陈晓云张少泉陈先富
Owner YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST
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