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CN-122000894-A - Capacitance current calculation method under distribution compensation

CN122000894ACN 122000894 ACN122000894 ACN 122000894ACN-122000894-A

Abstract

The invention provides a capacitance current calculation method under distribution compensation. The method comprises the steps of S1, fitting a bus zero-sequence transient voltage to a sine function with rectangular coordinates being a time function, S2, setting a line terminal zero-sequence voltage initial value, S3, calculating a bus zero-sequence voltage and a line outgoing zero-sequence current according to a line distribution parameter circuit model, S4, comparing the calculated value of the bus voltage with an actual value, calculating an error, S5, judging whether the error meets the precision requirement, outputting the line outgoing zero-sequence current if the error meets the precision requirement, and correcting the line terminal zero-sequence voltage initial value and repeating steps S3-S5 if the error does not meet the precision requirement. The calculation error of the invention can meet the requirement of capacitance current compensation, and the calculation time of the capacitance current is short, thereby meeting the requirement of on-line adjustment of the arc suppression coil.

Inventors

  • CAO HONGXIA
  • TANG DENGFENG
  • YAO YONG
  • XU MAOYUAN
  • WANG YUSHAN
  • WANG QIUYU
  • LIU HUAYI
  • WU SONGLIN
  • LUO LI
  • WANG JUNFEI

Assignees

  • 国网重庆市电力公司市区供电分公司

Dates

Publication Date
20260508
Application Date
20251218

Claims (8)

  1. 1. A method for calculating capacitance current under distributed compensation, the method comprising the steps of: S1, generating a bus zero sequence transient voltage Fitting rectangular coordinates is a sine function of a time function; s2, setting the zero sequence voltage of the line terminal according to the sine function fitted by S1 An initial value; S3, zero sequence current based on line terminal Sum zero sequence voltage Initial value, calculating zero sequence voltage of bus according to circuit model of circuit distribution parameters Zero sequence current of line outgoing line ; S4, calculating the bus voltage With actual voltage of bus Comparing and calculating an error e; s5, judging errors Whether the precision requirement is met, if so, outputting the line outlet zero sequence current And/or line termination zero sequence voltage If not, the zero sequence voltage of the line terminal is calculated And correcting the initial value, and repeating the steps S3-S5.
  2. 2. The method for calculating capacitance-current under distributed compensation according to claim 1, further comprising; S6, calculating all line outlet zero sequence currents of the substation bus connection, and then summing to obtain capacitance current of the power distribution network system.
  3. 3. The method for calculating a capacitance-current under distributed compensation according to claim 1, wherein in S1, the expression of the sine function is: ; Wherein, the 、 Constant terms of the abscissa fitting function, For fitting a functional polynomial The coefficient of the order term is used, Representing the polynomial order of the fitting function, Is that Is used in the conversion of the Hilbert transform, As an exponential function Ω is the angular frequency and t is the time.
  4. 4. The method for calculating capacitance-current under distributed compensation according to claim 1, wherein in S2, the line termination zero sequence voltage The calculation expression of the initial value is: ; The coefficients of which are: ; Where n is a set constant.
  5. 5. The method for calculating a capacitance current under distributed compensation according to claim 1, wherein in S3, the line distributed parameter circuit model includes: ; Wherein, the And Represented as ; Wherein R is the resistance of the unit length of the line, omega/km; L is inductance of a unit length of a line, and H/km; c is capacitance of unit length of line, F/km; G is the conductance of the line unit length, S/km; l is the length of the line, km; Representing slave Fetching from different elements A combination of individual elements; 、 Each representing Current and voltage at point in time N And (5) an order derivative.
  6. 6. The capacitance-current calculation method under distributed compensation according to claim 1, wherein in S4, the error e is calculated using the following formula: 。
  7. 7. the method for calculating capacitance-current under distributed compensation according to claim 1, wherein in S5, the accuracy requirement is within 5%.
  8. 8. The method for calculating a capacitance-current under distributed compensation according to claim 1, wherein in S5, the correction is performed using the following equation: 。

Description

Capacitance current calculation method under distribution compensation Technical Field The invention relates to the technical field of power system protection control, in particular to a capacitance current calculation method under distributed compensation. Background With the acceleration of the urban process, urban population is increased increasingly, land area shortage is accompanied with the problem of high load, the traditional overhead line cannot meet the increasing power demand, the power line occupation area can be reduced by introducing the cable line, but meanwhile, the capacity of the arc suppression coil compensation of the original transformer substation is limited, and when the capacity current cannot be compensated effectively, potential safety hazards such as resonance overvoltage and the like can occur in the power distribution network, so that a compensation device in the transformer substation needs to be upgraded, and one mode is to compensate the increased capacity current by adopting the distributed arc suppression coil. After the distribution compensation device is installed, the priority is that the distribution arc suppression coil is used for fixed compensation, and the residual current is compensated by the online adjustment of the arc suppression coil of the transformer substation. When the system suffers from single-phase earth faults, in order to safely adjust the arc suppression coils under distributed compensation on line, the capacitance current under the single-phase earth faults of the system needs to be calculated on line. The existing method for calculating the capacitance current is to set a current transformer on the outgoing line side for measurement, and for a power distribution network resonance grounding system additionally provided with a distribution compensation device, the capacitance current is difficult to measure by using the current transformer, so that uncertain factors appear in the on-line adjustment of an arc suppression coil, and the operation safety of the system is affected. Disclosure of Invention The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, one of the purposes of the invention is to reliably compensate the arc suppression coil and improve the safety of the power supply system. In order to achieve the above object, the present invention provides a method for calculating a capacitance current under distributed compensation. The method comprises the following steps of S1, enabling a bus zero sequence transient voltage to be the same as a zero sequence transient voltageS2, setting the zero sequence voltage of the line terminal according to the sine function fitted by S1Initial value S3, zero sequence current based on line terminalSum zero sequence voltageInitial value, calculating zero sequence voltage of bus according to circuit model of circuit distribution parametersZero sequence current of line outgoing lineS4, calculating the bus voltageWith actual voltage of busComparing, calculating error e, S5, judging errorWhether the precision requirement is met, if so, outputting the line outlet zero sequence currentAnd/or line termination zero sequence voltageIf not, the zero sequence voltage of the line terminal is calculatedAnd correcting the initial value, and repeating the steps S3-S5. S6, calculating all line outlet zero sequence currents of the substation bus connection, and then summing to obtain capacitance current of the power distribution network system. Optionally, in the S1, the expression of the sine function is: ; Wherein, the 、Constant terms of the abscissa fitting function,For fitting a functional polynomialThe coefficient of the order term is used,Representing the polynomial order of the fitting function,Is thatIs used in the conversion of the Hilbert transform, s is an exponential functionΩ is the angular frequency and t is the time. Optionally, in the step S2, the line terminal zero sequence voltageThe calculation expression of the initial value is: ; The coefficients of which are: ; Where n is a set constant. Optionally, in the step S3, the line distribution parameter circuit model includes: ; Wherein, the AndRepresented as ; Wherein R is resistance of line unit length, omega/km, L is inductance of line unit length, H/km, C is capacitance of line unit length, F/km, G is conductance of line unit length, S/km, L is length of line, km; Representing slave Fetching from different elementsA combination of individual elements;、 Each representing Current and voltage at point in time NAnd (5) an order derivative. Optionally, in the step S4, the error e is calculated using the following formula: 。 optionally, in the step S5, the accuracy requirement is within 5%. Optionally, in the step S5, the correction is performed using the following formula: 。 Compared with the prior art, the invention has the beneficial effects that: (1) The invention is not influenced by the distri