Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)

A positive-sequence impedance and differential protection technology, which is applied in the direction of automatic disconnection emergency protection devices, emergency protection circuit devices, electrical components, etc., can solve the problem of limited applicability, protection refusal to operate, and the change law of equivalent impedance on the back side of the protection Complicated and other problems, to improve the action characteristics, reduce the load branch, and ensure the effect of reliability

Active Publication Date: 2016-07-27
ZAOZHUANG POWER SUPPLY COMPANY OF STATE GRID SHANDONG ELECTRIC POWER +2
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Problems solved by technology

If random loads with different characteristics in the downstream are taken into account at the same time, the change rule of the equivalent impedance on the back side of the protection will be more complicated, and its impedance angle may exceed the fault criterion range of the positive direction of the fault componen

Method used

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  • Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)
  • Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)
  • Positive sequence impedance differential protection method with braking characteristic for power distribution network containing inverter-based distributed generation (IBDG)

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Embodiment Construction

[0046] The present invention is described in detail below in conjunction with accompanying drawing:

[0047] A positive-sequence impedance differential protection method for distribution networks with IBDG with braking characteristics, such as Figure 4 shown, including:

[0048] Install current transformers on the upstream and downstream sides of each distributed power access point on the active distribution network feeder, and use the voltage transformer at the grid-connected point of the distributed power to collect and protect the three-phase current and three-phase current at the installation site in real time. voltage; use the instantaneous value of three-phase current to determine the fault in the distribution network, and protect and start the fault processing program; determine the initial time of the fault, store the fault data of one cycle before and after the initial time of the fault, and compare the three-phase current amplitude before and after the fault value, t...

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Abstract

The invention discloses a positive sequence impedance differential protection method with braking characteristic for a power distribution network containing inverter-based distributed generation (IBDG). The method comprises the following steps of acquiring a three-phase current and a three-phase voltage at a protection position to acquire positive sequence impedance; carrying out information exchange between protection at two sides through an optical fiber Ethernet or a wireless communication network; carrying out calculation of action impedance and braking impedance by a local-side protection device after acquiring positive sequence impedance information and positive sequence current amplitude information which are measured by opposite-side protection; and judging whether a protected region is a fault section or not according to an action criteria with the baking characteristic. The method is applicable to circuit protection between a bus of a substation outlet of an active power distribution network and a distributed power supplies and between the distributed power supplies, the influence of fault characteristic of IBDG and through load current on protection performance can be dealt with, and the influence of a branch load on the judgment of a fault direction during an external fault can be prevented duo to the adoption of the action criteria; and moreover, data synchronism between two ends is not needed, the requirement on communication is relatively low, and the method has relatively high transition resistance resistant capability.

Description

technical field [0001] The invention relates to the technical field of relay protection for power systems, in particular to a positive-sequence impedance differential protection method with braking characteristics suitable for the operation characteristics of an inverter-type distributed power distribution network. Background technique [0002] Feeders of medium and low voltage distribution networks are often only equipped with circuit breakers at the head end of the line and equipped with three-stage current protection. The setting calculation focuses on sensitivity, and the automatic reclosing function of the head end protection or feeder automation guarantee is selected. After the inverter-based distributed generation IBDG (inverter-based distributed generation) is connected, when the upstream line of the IBDG fails, in order to isolate the faulty line from both sides of the fault point and prevent the transient fault from developing into a permanent fault, it is necessary...

Claims

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Application Information

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IPC IPC(8): H02H7/26H02H3/34
CPCH02H3/343H02H7/262
Inventor 陈宁王传勇邹贵彬徐萌韩蓬张健王坤杨凤文康文文代二刚孙宝峰
Owner ZAOZHUANG POWER SUPPLY COMPANY OF STATE GRID SHANDONG ELECTRIC POWER
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