CN-121984037-A - Reactive power dynamic compensation control method and device for traction power supply system

CN121984037ACN 121984037 ACN121984037 ACN 121984037ACN-121984037-A

Abstract

The invention discloses a reactive power dynamic compensation control method of a traction power supply system, which comprises the steps of obtaining the amplitude and the phase of an equivalent power supply voltage corresponding to a three-phase access point of a thyristor control compensator through measuring the primary voltage of a transformer and converting and calculating, detecting the voltage and the current of a two-phase traction network in real time, calculating to obtain total reactive power to be compensated based on an instantaneous reactive power theory, determining the triggering angle of each phase thyristor according to the total reactive power and the voltage amplitude, and generating and outputting a triggering signal for driving the thyristor to be conducted through comparing the triggering angle with the voltage phase of each phase. The method can realize dynamic tracking compensation of reactive power of the traction network, effectively improve the power factor of the traction substation, reduce the expenditure of power adjustment and electricity charge, improve the electric energy quality of the power network and expand the application of the dynamic reactive power compensation technology in electrified railways.

Inventors

Ning Yuanzhi
LUO LONGFU

Assignees

湖南大学

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (7)

1. A reactive power dynamic compensation control method for a traction power supply system, applied to a traction power supply system comprising a balancing transformer and a thyristor controlled compensator, characterized in that the method comprises: S1, measuring and calculating in real time to obtain the amplitude and the phase of the three-phase equivalent power supply voltage corresponding to the three-phase access point of the thyristor control compensator; S2, detecting the voltage and the current of the two-phase traction network in real time, and calculating to obtain the total reactive power which is required to be compensated by the thyristor control compensator currently based on the detected voltage and current; S3, determining a trigger angle for controlling each phase of thyristors in the thyristor control compensator according to the total reactive power and the amplitude; and S4, based on the comparison of the trigger angle and the phase information of each phase, generating and outputting a trigger signal for driving the thyristor to be conducted according to a comparison result.
2. The reactive power dynamic compensation control method of a traction power supply system according to claim 1, wherein the step S1 specifically includes collecting input voltage V A 、V B 、V C of primary side three-phase windings of a star-shaped open delta connection YNVD balance transformer, obtaining voltage V mc 、V cn 、V nm between m-c, c-n and n-m on a secondary side delta winding of the YNVD balance transformer according to a transformer port theory, and obtaining three-phase equivalent voltage V U 、V V 、V W corresponding to taps m and n and a bottom node c of the secondary side delta winding of the YNVD balance transformer according to a delta-Y voltage conversion relation; the voltage relation of the transformer port theory is as follows: Wherein V mc is the voltage between mc on the secondary side delta winding of YNVD balanced transformer, V cn is the voltage between cn on the secondary side delta winding of YNVD balanced transformer, and V nm is the voltage between nm on the secondary side delta winding of YNVD balanced transformer; V A is YNVD a-phase voltage input to the primary side of the balance transformer, V B is YNVD B-phase voltage input to the primary side of the balance transformer, and V C is YNVD C-phase voltage input to the primary side of the balance transformer; For the transformation ratio of the traction transformer, The winding turns ratio at m and n; Converting the voltage V mc 、V cn 、V nm between mc, cn and nm on the YNVD secondary side triangular winding of the balancing transformer into a three-phase equivalent voltage V U 、V V 、V W at the tap and bottom node positions of the secondary side triangular winding of the balancing transformer of YNVD, wherein the voltage conversion relationship of delta to Y is as follows: Wherein V U is the converted U-phase voltage, V V is the converted V-phase voltage, and V W is the converted W-phase voltage.
3. The method according to claim 1, wherein in step S2, calculating the total reactive power comprises: Detecting the voltage V α 、V β and the current i α 、i β of the alpha phase and the beta phase traction network in real time, obtaining V αd 、V βd obtained by delaying V α 、V β by 90 degrees and i αd 、i βd obtained by delaying i α 、i β by 90 degrees, respectively calculating reactive power Q αL 、Q βL consumed by locomotives on the alpha phase and the beta phase traction network, extracting direct current components of Q αL 、Q βL by a low-pass filter, and summing to obtain the total reactive power.
4. The method for dynamically compensating reactive power of a traction power supply system according to claim 3, wherein the specific calculation formula of the reactive power consumed by the locomotives on the α -phase and the β -phase traction network is as follows: Wherein Q αL is reactive power consumed by locomotives on an alpha-phase traction network, Q βL is reactive power consumed by locomotives on a beta-phase traction network, V α is voltage of the alpha-phase traction network, V β is voltage of the beta-phase traction network, i α is current of the alpha-phase traction network, i β is current of the beta-phase traction network, V αd is obtained by delaying V α by 90 degrees, V βd is obtained by delaying V β by 90 degrees, i αd is obtained by delaying i α by 90 degrees, and i βd is obtained by delaying i β by 90 degrees; the total reactive power calculation formula is as follows: In the formula, Is the direct current component of the alpha phase instantaneous reactive power Q αL , Is the direct current component of the beta-phase instantaneous reactive power Q βL .
5. The method for dynamic compensation control of reactive power of a traction power supply system according to claim 1, wherein determining the firing angle in step S3 comprises controlling compensator element parameters based on the three-phase equivalent voltage, the total reactive power and a preset thyristor, by querying a preset one And determining the triggering angle alpha by a corresponding relation table of the triggering angle alpha of the thyristor.
6. The method according to claim 1, wherein the step S4 specifically includes generating a trigger signal for turning on the thyristor T i1 when θ i > α, and generating a trigger signal for turning on the thyristor T i2 when θ i <180 ° - α.
7. A reactive power dynamic compensation control device of a traction power supply system is characterized by comprising a YNVD balance transformer and a thyristor control compensator TCLCB, wherein a primary side winding of the YNVD balance transformer is respectively connected with an A phase, a B phase and a C phase of a three-phase power grid, a secondary side winding provides two 27.5 kV-level voltages for an alpha phase electric locomotive and a beta phase electric locomotive respectively to supply power, each of the three phases of the TCLCB is formed by connecting a pair of anti-parallel thyristors with an inductor L T in series to form a series branch, the series branch is connected with a capacitor C PF in parallel to form a parallel compensation unit, each phase of the parallel compensation unit is connected with the inductor L PF in series to form an integral compensation branch of the phase, each phase of the TCLCB is respectively connected to taps m, n and a bottom node C of a secondary side triangle winding of the YNVD balance transformer, the other end of the TCLCB is connected by adopting a star connection method, a common point is O point, and the secondary side triangle taps of the TCB and the YNVD balance transformer are connected with the bottom node.

Description

Reactive power dynamic compensation control method and device for traction power supply system Technical Field The invention belongs to the field of electrified railway power supply, and particularly relates to a reactive power dynamic compensation control method and device of a traction power supply system. Background When the reactive power consumed by the electric locomotive is excessive, the voltage at the tail end of the traction network is too low, and the normal operation of the electric locomotive is affected seriously. In order to improve the power factor of the traction substation, the prior art proposes to carry out reactive compensation by hooking a capacitor bank on a two-phase traction feeder, and the implementation method is simpler, but when the traction feeder is in a light load condition, the problem of reactive power overcompensation exists, so that the voltage of the traction network is possibly out of limit to cause tripping of a relay protection device. It is also proposed to connect the H-bridge cascaded inverter to the traction network via a single-phase step-down transformer, which is capable of dynamically compensating the reactive power of the traction network, but has the disadvantages of high cost, complex control, need to add an additional step-down transformer with large capacity, and the like. It is also proposed to directly connect the series circuit of the capacitor and the two thyristors connected in anti-parallel with the inductor to the traction network, and the method can dynamically compensate the reactive power to a certain extent by adjusting the firing angle of the thyristors, but if the voltage born by the thyristors is too high when a single thyristor is used for connection, a plurality of thyristors need to be connected in series for use, so that the problems of complex control and high failure rate exist. The method reduces the voltage level of the connection of the inductance and capacitance series branch, and can improve the power factor of the traction substation to a certain extent, but the method for fixing and compensating has the defect of reactive power overcompensation or undercomplement due to the randomness and fluctuation characteristics of the load power of the railway locomotive. Disclosure of Invention The invention provides a reactive power dynamic compensation control method of a traction power supply system, which realizes dynamic compensation of traction load reactive power by detecting voltage and current signals of a traction network in real time and effectively improves the power factor of a traction substation. The invention provides a reactive power dynamic compensation control method of a traction power supply system, which is applied to the traction power supply system comprising a balance transformer and a thyristor control compensator, and comprises the following steps: S1, measuring and calculating in real time to obtain the amplitude and the phase of the three-phase equivalent power supply voltage corresponding to the three-phase access point of the thyristor control compensator; S2, detecting the voltage and the current of the two-phase traction network in real time, and calculating to obtain the total reactive power which is required to be compensated by the thyristor control compensator currently based on the detected voltage and current; S3, determining a trigger angle for controlling each phase of thyristors in the thyristor control compensator according to the total reactive power and the amplitude; and S4, based on the comparison of the trigger angle and the phase information of each phase, generating and outputting a trigger signal for driving the thyristor to be conducted according to a comparison result. Preferably, the step S1 specifically includes collecting an input voltage V A、VB、VC of a primary side Three-Phase winding of a star-shaped open delta-delta connection YNVD balance transformer (Three-Phase to Two-Phase Traction Balancing Transformer), obtaining voltages V mc、Vcn、Vnm between m-c, c-n, n-m on a secondary side delta-winding of the YNVD balance transformer according to a transformer port theory, and obtaining Three-Phase equivalent voltages V U、VV、VW corresponding to taps m, n and a bottom node c of the secondary side delta-winding of the YNVD balance transformer according to a delta-Y voltage conversion relationship; the voltage relation of the transformer port theory is as follows: Wherein V mc is the voltage between mc on the secondary side delta winding of YNVD balanced transformer, V cn is the voltage between cn on the secondary side delta winding of YNVD balanced transformer, and V nm is the voltage between nm on the secondary side delta winding of YNVD balanced transformer; V A is YNVD a-phase voltage input to the primary side of the balance transformer, V B is YNVD B-phase voltage input to the primary side of the balance transformer, and V C is YNVD C-phase voltage input to the primary side of the balan