Method for calculating and cutting off overloads of city power grid including electric vehicle

Abstract

The invention discloses a method for calculating and cutting off overloads of a city power grid including an electric vehicle. The method comprises the following steps: A, modeling of uncertain factors of the city power grid; B, calculation of probabilistic power flow during fault occurrence, wherein branch power flow and node voltage probability distribution of the city power grid during fault occurrence is calculated by adopting a probabilistic power flow algorithm; C, the method for calculating and cutting off the overloads, wherein power flow overload probability of each branch and voltage exceeding probability of each node are obtained based on a result in the step B, a load cutoff condition is confirmed, and analysis is carried out from a downstream line to an upstream line, that is to say, cutoff is carried out on three-stage loads of the node meeting the load cutoff condition, if the load capacity of the three-stage loads is smaller than the overload capacity, cutoff is carried out from a third-stage load to a second-stage load and a first-stage load in sequence from a superior node to a subordinate node until all the overloads are cut off. The method is high in reliability, and the overload capacity prediction meets an actual operation condition of the city power grid, so that the safety of the city power grid is guaranteed.

Description

technical field [0001] The invention relates to a method for calculating and removing the overload of an urban power grid containing electric vehicles, and belongs to the technical field of power system operation analysis. Background technique [0002] Urban grid overload calculation is an important field in power system research and one of the important tasks of urban grid dispatching, planning, planning and other departments. It is related to the safety, economy and power supply quality of urban grid operation. Existing studies on shedding overload are all based on deterministic power flow calculations to obtain the shedding load. The deterministic power flow calculation does not consider the random change factors in the power system, that is, the value of each node voltage and branch power flow is calculated on the basis of definite values ​​such as network topology, component parameters, and node loads. There are various random factors in the urban power grid. If the de...

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Problems solved by technology

There are various random factors in the urban power grid. If the deterministic power flow is used for calculation, a large number of scheme calculations are required for many possible situations. Not only the calculation amount is large, but it is also difficult to fully reflect the operation status of the system

In addition, with the construction of urban power grids and the development of the electric vehicle industry, electric vehicles have attracted widespread attention from the market and users due to their low emissions, low noise, high energy efficiency, and intelligence. Compared with other electricity loads, electric vehicles It has strong randomness and intermittence, which has a great impact on the safe and stable operation of the urban power grid. The existing overload calculation method does not consider the charging load of electric vehicles in the urban power grid, so the calculated results are far from the actual system deviation. Big

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