Same-tower double-loop AC power transmission line parameter measuring and calculating method

Abstract

The invention discloses a same-tower double-loop AC power transmission line parameter measuring and calculating method. The method comprises the following steps: dividing a same-tower double-loop power transmission line into three wiring modes; measuring open-circuit impedance and short-circuit impedance under the condition of each wiring mode; by use of measuring results of the open-circuit impedance and the short-circuit impedance under the condition of each wiring mode, calculating characteristic impedance and a propagation coefficient under each corresponding wiring mode, and further calculating distribution impedance and distribution admittance under the corresponding mode; and finally, through the distribution impedance and the distribution admittance under each wiring mode, establishing a system of simultaneous equations, and calculating resistance, inductance and grounding capacitance of each lead wire of the same-tower double-loop line, alternate coupling capacitance and alternate coupling inductance of a single-loop line and coupling capacitance and coupling inductance between each lead wire of a double-loop line. According to the invention, error factors are avoided, various parameters of the same-tower double-loop power line at the frequency of omega can be accurately obtained, a reliable and accurate data source is provided for various calculation of a power system, and the calculation result is enabled to be more accurate.

Description

technical field [0001] The invention relates to the technical field of power system parameter measurement, in particular to a method for measuring and calculating parameters of double-circuit AC transmission lines on the same tower. Background technique [0002] Accurate transmission line parameters are crucial to power system power flow stability analysis, protection setting, fault location, etc. Since the birth of the power system, efforts to accurately measure transmission line parameters have never ceased. [0003] Due to the limitation of transmission line corridors, EHV AC transmission lines are often designed to be paralleled with double circuits on the same tower, or the two circuits share the corridor. figure 1 It is a typical double-circuit parallel AC transmission line with three-phase transposition. It is generally believed that the line parameters of the three-phase conductors after transposition are symmetrical. [0004] The transmission line has the charact...

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Problems solved by technology

[0016] The problem here is: when measuring the zero-sequence open-circuit impedance and short-circuit impedance of a single-circuit line, because the zero-sequence current and zero-sequence voltage of the three-phase line must pass through the coupling capacitor C between the double-circuit lines LL and coupled inductor M LL Influence another circuit (see Figure 13 ), so the zero-sequence open-circuit impedance and short-circuit impedance of the single-circuit line in this state are not the zero-sequence open-circuit impedance and zero-sequence short-circuit impedance of the single-circuit line alone

[0017] It can be seen that the transmission line parameters obtained by the existing measurement and calculation methods have large errors and need to be improved

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