RU-2861400-C1 - METHOD FOR CONTROLLING MULTI-STEP CAPACITOR-REACTOR VOLTAGE AND REACTIVE POWER REGULATOR ON HIGH-VOLTAGE SIDE OF TRANSFORMER SUBSTATION

RU2861400C1RU 2861400 C1RU2861400 C1RU 2861400C1RU-2861400-C1

Abstract

FIELD: electrical engineering. SUBSTANCE: invention relates to electric power systems, and can be used for continuous provision of combined compensation of voltage deviation (fluctuation) and reactive power on the high-voltage side of a transformer substation with high accuracy and energy indicators when increasing and decreasing the voltage of the supply network and load current over a wide range and ranges. For optimal control of a transformer substation under stationary and dynamic operating modes of electric power systems, to facilitate and ensure normal operation of electrical equipment, as well as to increase the accuracy of combined voltage and reactive power regulation, feedback in the substation is generated on the high and low sides of the power transformer. Feedback on the high side of the power transformer is based on the effective value of the supply network voltage U 3 , and on the low side – on the effective value of the load reactive power Qh. In the claimed method for controlling a multi-step capacitor-reactor voltage and reactive power regulator, one of the options for changing the voltage in the supply network and the load current is considered. The controlled device has the ability to provide continuous and combined compensation of voltage deviation and reactive power in electric power systems under different variants of deviations (fluctuations) of the supply network voltage and/or load current with high accuracy and energy indicators. An appropriate area of application of the claimed method for controlling a multi-step capacitor-reactor voltage and reactive power regulator is electric power systems with voltages of 35/(10-6) kV and (10-6)/0.4 kV, where there is a need for continuous provision of combined compensation of voltage deviation and reactive power at a given level with high accuracy and technical-economic indicators at different levels of deviations (fluctuations) of the supply network voltage and/or load current over a wide range and ranges. EFFECT: switching on and off of power transformers with high energy indicators, expanding the limit and range of voltage and reactive power regulation at the lowest cost, as well as continuous provision of combined compensation of voltage deviation (fluctuation) and reactive power on the high-voltage side of the transformer substation with high accuracy and efficiency at different levels of supply network voltage and/or load current. 1 cl, 4 dwg

Inventors

Tabarov Bekhruz Dovudkhodzhaevich

Dates

Publication Date: 20260505
Application Date: 20251111

Claims (1)

A method for controlling a multi-stage capacitor-reactor voltage and reactive power regulator on the high-voltage side of a transformer substation, comprising blocks of multi-stage capacitor-thyristor and reactor-thyristor starting devices, where the block of the multi-stage capacitor-thyristor starting device consists of a set of a compensating device, a module of thyristor keys, blocks of a bank of cosine capacitors and a discharge device, and the block of the multi-stage reactor-thyristor starting device is a three-phase contactor, modules of the main and additional thyristor keys, as well as the main and additional reactors, where before turning on and off the power transformer of the substation together with the block of the multi-stage capacitor-thyristor starting device, the pulse-phase control system generates pulses and feeds them through the corresponding output channels to the on/off coil of the high-voltage network switch and the high-voltage switch of the block of the multi-stage capacitor-thyristor starting device for switching on/de-energizing the multi-stage capacitor-reactor voltage and reactive power regulator unit, after which the pulse-phase control system receives information from the voltage and reactive power sensors about the voltage level of the supply network and the reactive power of the load through the automatic regulation unit for generating pulses and feeding them through the corresponding output channels to the control inputs of the multi-stage capacitor-reactor voltage and reactive power regulator unit for joint switching on/off of the substation power transformer and the compensating device kit of the multi-stage capacitor-thyristor starting device unit, as a result of which, upon command from the pulse-phase control system, first two main and/or additional thyristor switches through the main and/or additional reactors of the multi-stage reactor-thyristor starting device unit connect two phases of the primary winding of the substation power transformer to the corresponding phases of the supply network at the moment of the phase voltage of the third phase of the supply network crossing zero, then a third main and/or additional thyristor switch through the main and/or additional reactors of the unit the multi-stage reactor-thyristor starting device connects the third phase of the primary winding of the substation power transformer to the third phase of the supply network at the moment of the line voltage of the other two phases of the supply network crossing zero and, in parallel with this, also under the action of the pulse-phase control system of two thyristor keys of the multi-stage capacitor-thyristor starting device unit, connects two phases of the compensating device set to the corresponding phases of the supply network at the moment of the line voltage of the other two phases of the supply network crossing zero, and then, by the third thyristor key of the multi-stage capacitor-thyristor starting device unit, connects the third phase of the compensating device set to the third phase of the supply network at the moment of the phase voltage of the supply network crossing zero, as a result of which the substation power transformer and the compensating device set are switched on without the occurrence of starting currents, voltage sags and uneven load distributions across the phases with high energy indicators, after which the pulse-phase control system, taking into account the values supply network voltage and reactive power of the load, generates pulses and feeds them through the corresponding output channels to the control inputs of the multi-stage capacitor-reactor voltage and reactive power regulator unit for comprehensive provision of continuous regulation of voltage and reactive power, which is performed on the high-voltage side of the transformer substation and is achieved by the multi-stage capacitor-thyristor starting device unit with a constant capacitance and the multi-stage reactor-thyristor starting device unit with variable inductance of the main and additional reactors, which maintain a balance in electric power systems between the reactive power generated by the multi-stage capacitor-thyristor starting device unit and the total reactive power consumed by the load and the reactors of the multi-stage reactor-thyristor starting device unit, and thus the voltage in electric power systems is maintained at the nominal level with simultaneous compensation of reactive power, and before the joint shutdown of the substation power transformer and the compensating device set in the system pulse-phase control generate pulses for their shutdown and through the corresponding output channels feed them to the control inputs of the corresponding modules of the thyristor keys of the multi-stage capacitor-reactor voltage and reactive power regulator unit in the reverse sequence of the switching-on algorithm, as a result of which the substation power transformer and the compensating device set are switched off simultaneously without the occurrence of an electric arc, switching losses and overvoltages, characterized in that in order to expand the functionality of the multi-stage capacitor-reactor voltage and reactive power regulator unit when switching the transformer substation on and off, as well as comprehensively ensure continuous regulation of voltage and reactive power with high accuracy and energy indicators, in the event of deviations and fluctuations in the supply network voltage and load current over wide limits and ranges, the capacity of the compensating device set of the multi-stage capacitor-thyristor starting device unit is divided into four parts, and thus the multi-stage capacitor-thyristor starting device unit contains the first, second, third and fourth sets of compensating devices consisting of the corresponding modules thyristor switches, shunt contactor units, a bank of cosine capacitors and discharge devices, and the inductance of the main and additional reactors of the multi-stage reactor-thyristor starting device unit is divided into the main intermediate and additional intermediate reactors, respectively, in addition, for switching on and off the introduced reactors, the main intermediate and additional intermediate thyristor switches are introduced into the multi-stage reactor-thyristor starting device unit, which, together with a three-phase contactor and the corresponding modules of the main and additional thyristor switches, shunt or unshun the corresponding reactors when switching on, switching off and comprehensively regulating the voltage and reactive power, which depend on the level of the supply network voltage and/or load current, and before switching on, switching off and comprehensively regulating the voltage and reactive power with high accuracy and energy indicators, the pulse-phase control system receives information on the level of the actual value of currents and voltages from the supply network voltage sensors and the reactive power of the load through the automatic regulation unit electric power systems, and then forms them and, through the corresponding output information channels, feeds them to the control inputs of the thyristor switch modules of the multi-stage capacitor-reactor voltage and reactive power regulator unit for the joint switching on and off of the substation power transformer and the corresponding set of compensating devices with high energy performance by switching them on and off at nominal voltage, despite the current and voltage instabilities in electric power systems, as well as for continuous provision of complex regulation of voltage and reactive power in electric power systems with high accuracy and technical and economic indicators, which are achieved by the capacity of the battery of cosine capacitors of the first, second, third and fourth sets of compensating devices of the multi-stage capacitor-thyristor starting control device and the inductance of the main, additional, main intermediate and additional intermediate reactors of the corresponding modules of the main, additional, main intermediate and additional intermediate thyristor switches by maintaining a balance in electric power systems between the reactive power generated by the sets compensating devices of the multi-stage capacitor-thyristor starting device unit, and the total reactive power consumed by the load and the reactors of the multi-stage reactor-thyristor starting device unit, in addition, in order to improve the operational characteristics of the thyristor switch modules of the third and fourth sets of compensating devices, corresponding shunt contactor units are introduced for shunting the thyristor switch modules of the third according to the switching results or corresponding power-law capacitor bank units of the third and fourth sets of compensating devices to the power supply network, wherein when switching on and off the power-law capacitor bank units, the shunt contactor units are switched off and put them into operation upon completion of switching on the power-law capacitor bank units, wherein the switching on of the shunt contactor units is performed simultaneously with the removal of control pulses from the corresponding thyristor switch modules of the third and fourth sets of compensating devices of the multi-stage capacitor-thyristor starting device unit, and when switching off the power-law capacitor bank units, the system The pulse-phase control system generates pulses and supplies them in parallel to turn on the corresponding thyristor switch modules and to turn off the corresponding shunt contactor blocks of the third and fourth sets of compensating devices, and upon completion of turning on the thyristor switch modules and turning off the shunt contactor blocks in the pulse-phase control system, pulses are generated and supplied in parallel to the control inputs of the corresponding thyristor switch modules to turn off the corresponding blocks of the power-law capacitor bank of the first, second, third and fourth sets of compensating devices with high technical and economic indicators.

Description

The technical solution, on which the proposed control method is implemented, relates to electrical engineering, in particular to electric power systems, and can be used to continuously ensure joint compensation of voltage deviations (fluctuations) and reactive power on the high-voltage side of a transformer substation with high accuracy and energy indicators when increasing and decreasing the supply network voltage and load current over wide limits and ranges. A known method for controlling a multi-stage capacitor-reactor voltage and reactive power regulator on the high-voltage side of a transformer substation (Russian Federation Patent for Invention No. 2746796, H02J 3/18, published on April 21, 2021, BI No. 12. Application No. 2020133987 dated October 15, 2020), according to which reactive power compensation is ensured in the substation when deviations and fluctuations in the reactive power of the load occur over wide limits and ranges. The technical solution, which implements the known control method, is based on three sets of compensating devices with a power ratio of 1:2:4. The known method has high response speed and the ability to provide reactive power regulation over wide limits and ranges. The disadvantages of the known method include low accuracy of reactive power regulation, especially when the transformer is operating closer to idle mode, as well as the inability to stabilize the voltage in the substation with simultaneous compensation of reactive power. A method for controlling a multi-stage capacitor-reactor voltage and reactive power regulator on the high, medium and low voltage side of a transformer substation is also known (RU Patent for Utility Model No. 26870, H02J 3/16, H02J 3/18, published on 20.12.2002), which ensures stabilization of voltage and reactive power in electric power systems when deviations and fluctuations in the supply network voltage and/or reactive power of the load occur within wide limits and ranges. The technical solution, which implements the known control method, is built on the basis of a mechanical on-load voltage regulator (OLTC) and reactor units, where the mechanical device of the OLTC type is connected on the high voltage side of the power transformer, and the reactor units are connected to the low voltage buses through the corresponding switches. To control the device when combined voltage and reactive power stabilization is required, feedback is provided based on the supply network voltage and load reactive power via corresponding voltage and reactive power (current) sensors, which are connected to the high-voltage and medium-voltage sides of the transformer, respectively. This known control method enables combined voltage and reactive power stabilization over wide limits and ranges. Disadvantages of this known method include low response speed and accuracy of voltage and reactive power regulation, as well as a large number of switching devices and low technical and economic indicators. The closest in physical essence is the method for controlling a multi-stage capacitor-reactor voltage and reactive power regulator on the high-voltage side of a transformer substation (Method for indirect compensation of reactive power with simultaneous voltage stabilization: patent 2826951 Russian Federation: IPC: H02J 3/18 / Tabarov B.D.; applicant and patent holders Komsomolsk-on-Amur State University, -No. 2024107806; declared 03/25/2024; published 09/19/2024, Bulletin No. 26. - 14.), which is taken as a prototype. The prototype method is implemented using an unregulated capacitor bank and adjustable reactors with a mixed-connected power contactor and corresponding thyristor switch modules. The method provides indirect reactive power compensation (IRC), which consists of a fixed-capacity capacitor bank connected in parallel to the power grid and a power transformer, while reactors with corresponding thyristor switch modules are connected in parallel to the capacitor bank and in series to the power grid and a power transformer, thus maintaining a balance between the reactive power generated by the capacitor bank and the reactive power consumed by the load and the reactors with corresponding thyristor switch modules. The advantages of the prototype method include its application to both single-stage capacitor banks and interstage capacitor banks with fixed capacitances. It also improves power quality, increases transmission line capacity, and reduces additional power losses during low-voltage conditions in the power grid due to upward shifts in the external load characteristic or downward shifts in the external power grid characteristic. Another advantage of the prototype method is its ability to maintain the nominal voltage at the input and output of the substation power transformer during fluctuations and variations in the power grid voltage and/or load current. The disadvantages of the prototype method include, first of all, relatively large voltage distortions at the