Medium voltage distribution-network looped-network switching operation method

A switching operation, ring network technology, applied in the direction of electrical components, circuit devices, etc., can solve frequent power outages, losses, power supply management and user inconvenience and economic problems, to improve operating efficiency, ensure safe operation, and ensure line phase sequence consistent effect

Inactive Publication Date: 2013-01-09
STATE GRID CORP OF CHINA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional construction method needs to carry out power outage switching operation before and after maintenance, and the power outage is 20-30

Method used

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  • Medium voltage distribution-network looped-network switching operation method
  • Medium voltage distribution-network looped-network switching operation method
  • Medium voltage distribution-network looped-network switching operation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Power flow calculation method and calculation software

[0018] Power flow calculation can be reduced to solving nonlinear equations mathematically, and its mathematical model is abbreviated as follows:

[0019] F(X ) = 0 is a nonlinear system of equations

[0020] in:

[0021] F= ( f1 , f2 ,……, f n ) T is the node balance equation;

[0022] X= (x1 , x2 , … , x n ) T is the voltage of each node to be obtained.

[0023] Calculation software: "Power System Analysis Comprehensive Program" (PSASP) developed and compiled by EPRI can be used.

[0024] Such as figure 2 Shown: Taking the simplified loop closing process diagram of 110kV Jianxi Substation and 110kV Binhe Substation in Nanyang Power Grid as an example, it is assumed that the busbar voltage nodes 1 and 2 of the high-voltage side of the Jianxi Substation and Binhe Substation before the ring closure are U1 and U2 respectively, and the medium-voltage side 3 , 4 nodes U3, U4, the transmission power is Sa, Sb re...

Embodiment 2

[0027] short circuit calculation

[0028] The most serious three-phase short-circuit current does not exceed the breaking capacity of the switch as the criterion, and when it exceeds, the ring network operation is abandoned. Mainly calculate the ring closing moment:

[0029] (1) A three-phase short circuit occurs in the loop closing line;

[0030] (2) A three-phase short circuit occurs on the 10kV busbar;

[0031] (3) A three-phase short circuit occurs on the 110 kV bus;

[0032] (4) A three-phase short circuit occurred on the 220 kV bus.

[0033] If the short-circuit current in the above four situations does not exceed the breaking capacity of the switch at each voltage level, the

[0034] Switches at all levels have no effect.

[0035] Such as Figure 4 Shown: Short-circuit current calculation table for the second line of 10kV west supply line and second line of 10kV coastal power supply at the moment of ring closing. It can be seen from the table that at the moment of...

Embodiment 3

[0037] Such as figure 1 As shown, a medium-voltage distribution network ring switching operation method includes the following steps:

[0038] f. Carry out closed-loop power flow calculation and short-circuit calculation analysis, and use the non-exceeding protection setting value and equipment dynamic stability limit as criteria to assist dispatching decisions;

[0039] g. Check the phase sequence on site to ensure that the line phase sequence of the ring network operation is consistent;

[0040] h. First close the contact switch L1 between substation A and B;

[0041] i. Separate the section switch K1 of the fault line A near the end of the tie switch L1;

[0042] j. Finally, disconnect the section switch Z1 of the faulty line A near the A end of the substation.

[0043] The present invention adopts the method of ring network switching operation. Before the ring network switching, it should carry out the calculation of the closing current, short-circuit calculation and an...

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PUM

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Abstract

The invention discloses a medium voltage distribution-network looped-network switching operation method. Loop closing load flow calculation, short circuit calculation analysis and the existing site checking phase sequence are carried out before looped-network switching, a non-out-of-limit protection constant value and equipment dynamic and static limits are guaranteed, line phase sequences of looped-network operation is guaranteed, loop closing time is controlled to be minimum, the shorter the loop closing time is, the better the effects are, unforeseen circumstances such as line overload, relaying protection movement tripping, short circuits of closing loop moment power grids, damage to safety of lines and equipment and even equipment damage caused by big circulation are effectively avoided, safe operation of the power grid is guaranteed, operating efficiency of the power distribution network is effectively improved, and adverse effects of construction and overhaul on power supply management and users are effectively avoided.

Description

technical field [0001] The invention relates to the technical field of electric power maintenance technology, in particular to a switching operation method for a ring network of a medium-voltage distribution network. Background technique [0002] The urban medium-voltage distribution network is directly oriented to the majority of urban users. With the development of the city, construction and maintenance are becoming more and more frequent. In the traditional construction method, before and after maintenance, power outage switching operation is required, and the power outage is 20-30 minutes each time, resulting in frequent power outages, causing a lot of inconvenience and huge economic losses to power supply management and users. Contents of the invention [0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a medium-voltage distribution network ring network switching operation method that can carry out power grid main...

Claims

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Application Information

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IPC IPC(8): H02J13/00
Inventor 郭雪丽杜九菊齐昌宵马涛李新
Owner STATE GRID CORP OF CHINA
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