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Improved calculation method for classical assumption of short-circuit current

A classic assumption, short-circuit current technology, applied in the field of electric power, can solve the problem of under-consideration in the calculation of potential effects, and achieve the effect of ensuring a safety margin

Inactive Publication Date: 2014-04-09
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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Problems solved by technology

[0005] The present invention aims at the problem of under-consideration of the influence on the calculated potential in the existing classic short-circuit current assumption method, and proposes an improved calculation method for the classic assumption of short-circuit current. The method uses the sub-transient potential of the generator to calculate the potential. State of result accuracy, improved safety

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Embodiment Construction

[0017] The specific implementation steps of the classic hypothesis improvement method are as follows:

[0018] (1) Calculate the subtransient potential of each generator under the planned maximum operation mode (the planned maximum operation mode refers to the operation mode of the system under the maximum planned power generation load) ( is the number of generators), the calculation formula is as follows:

[0019] (1)

[0020] In the formula, respectively generator ( ) active power, reactive power output and terminal voltage under the planned maximum operation mode, are the stator resistance and subtransient reactance of the generator, respectively.

[0021] (2) The node admittance matrix is ​​formed using classical assumptions, which include the following conditions:

[0022] A: Use the average rated voltage as the voltage reference, ignoring the difference between the rated voltage of each component and the average rated voltage of the corresponding voltage...

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Abstract

The invention relates to an improved calculation method for classical assumption of short-circuit current. Based on practical calculation of the short-circuit current in classical assumption, subtranient potential of a generator is used as calculation potential. Compared with a traditional practical calculation method for short-circuit current, the method has the advantages that the subtranient potential of the generator instead of voltage before short circuit of a fault point in the traditional practical calculation method is used as the calculation potential, and accordingly the safety margin of short-circuit current calculation results can be ensured without reducing calculation precision.

Description

technical field [0001] The invention relates to a power technology, in particular to a calculation method for the short-circuit current of a power system. Background technique [0002] Short circuit is a serious fault in the power system. Accurate calculation of short circuit current is very important for selecting electrical equipment, configuring relay protection and automatic devices. At present, the calculation methods of conventional short-circuit current are mainly based on power flow and based on classical assumptions. [0003] The short-circuit current calculation method based on power flow considers the influence of generator potential, load, ground branch, parallel compensation, and non-standard transformation ratio of the transformer. , which is closest to the actual short-circuit current. However, this method must first determine the power generation and its distribution on the transmission and distribution network (ie power flow distribution) according to the ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R19/00
Inventor 曹炜戈睛天祁晓卿张西竹郑晟杨文清
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER