Method for estimating loop-closing operation safety of medium-voltage power distribution network

Abstract

The invention discloses a method for estimating loop-closing operation safety of a medium-voltage power distribution network. The method comprises the steps of acquiring a topological structure, an equipment parameter and real-time running data of a loop-closing network, and estimating a state of a high-voltage power distribution network to obtain voltage amplitude and a phase angle of a 10kV busat an initial end of a loop-closing feeder; selecting a ratio between an active power load and a reactive power load of each load point on the loop-closing feeder and a ratio between an active power and a reactive power of the initial end of the feeder as input variables, and calculating each order semi invariant of the input variables according to historical load data; performing certainty powerflow and loop-closing current calculation; calculating each order semi invariant of a loop-closing current; solving accumulation probability distribution of the loop-closing current; and calculating out-of-limit probability of each loop-closing current, and estimating safety of the loop-closing operation. By the method, the loop-closing operation safety of the medium-voltage power distribution network can be quantitatively estimated, the problem that the real-time load data of each load point in the feeder in practice cannot be acquired is solved, and the problem that a probability distribution function of the input variable is needed to be known during solving the semi variant by a traditional numerical method is also solved.

Description

technical field [0001] The invention relates to the field of safe and stable operation of electric power systems, in particular to a method for evaluating the safety of loop closing operation of a medium-voltage distribution network. Background technique [0002] The medium-voltage distribution network adopts the power supply mode of closed-loop design and open-loop operation. Under normal circumstances, the contact switch is opened, and the distribution network operates in a radial structure; during equipment maintenance or accident handling, the load can be transferred without power failure through the loop closing operation of the contact switch. The loop-closing operation of the medium-voltage distribution network may generate a large loop-closing current in the loop-closing network, causing line current protection actions or overloading of some electrical equipment, resulting in a wider range of power outages. Therefore, operators need to evaluate its safety before clo...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a method for assessing the safety of the loop closing operation of the medium-voltage distribution network. Aiming at the problem that the voltage phase angle data of each bus in the distribution network cannot be obtained, a method for state estimation of the high-voltage distribution network is adopted To get the bus phase angle information

Aiming at the problem that the real-time load data of feeder load points required for loop closure current calculation cannot be obtained, the probability distribution characteristics of load values ​​at each load point are first analyzed based on historical load data, and then based on the probability power flow theory, the half-step variable method is used to obtain the loop closure The cumulative distribution curve of the current, and finally evaluate the safety of the loop-closing operation by calculating the probability of the loop-closing current exceeding the limit

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