Reactive power coordinated control system and control method for multiple pumped-storage units with system voltage constraints

Abstract

The present invention belongs to the field of pumped-storage power systems, and particularly relates to a reactive power coordination control system and a control method for multiple pumped-storage units with system voltage constraints, which solve the technical problems that the reactive power output of multiple pumped-storage units cannot be reasonably coordinated and utilized, and the reactive power output of the units does not consider the system substation voltage constraints. A first voltage transformer is connected in parallel to the high-voltage bus of the access system substation, the secondary end of the first voltage transformer is connected to the input end of a first voltage collector through a signal acquisition line, and the output end of the first voltage collector is connected to the signal input end of the control station; a second voltage transformer is connected in parallel to the high-voltage bus of the pumped-storage power station, the secondary end of the second voltage transformer is connected to the input end of a second voltage collector through a signal acquisition line, and the output end of the second voltage collector is connected to the signal input end of the control station; the output end of the control station is connected to the input ends of a plurality of the unit excitation regulators.

Description

Technical Field

[0001] The present invention belongs to the field of pumped - storage power systems, and particularly relates to a reactive power coordination control system and a control method for multiple pumped - storage units with system voltage constraints. Background Art

[0002] As a type of hydro - power unit, pumped - storage units have multiple operating modes such as power generation, pumping, leading - phase operation, and in - phase operation. In different operating modes, the reactive power output of multiple pumped - storage units needs to be coordinated. Otherwise, there will be problems such as the simultaneous existence of leading - phase and lagging - phase operations of multiple units, which will affect the safe operation of the system. At the same time, there are operating constraints on the system substation voltage. In different operating modes of pumped - storage units, different reactive power supports need to be provided to the system to meet the operating requirements. However, the current relevant research does not cover this aspect. Jiang Yijing, Voltage Control of Tianhuangping Pumped - Storage Power Station [J], proposed voltage regulation means for a certain pumped - storage power station, but only with voltage as the regulation target; Chen Wen, Cui Yibo, You Li, etc., Comparison of the Effects of Different Operating Modes of Pumped - Storage Units on Grid Voltage Regulation [J], analyzed the voltage regulation effects of pumped - storage units in different operating modes by experimental means; Hao Xinjie, Song Shuyong, Zheng Huiping, etc., Research on Reactive Power Voltage Control of Pumped - Storage Units in Motor Operating Mode [J], described the voltage regulation ability and stability of a certain pumped - storage unit through simulation and experimental means. Although the above - mentioned literatures have studied the influence of system voltage regulation for pumped - storage units, the above - mentioned literatures do not consider the coordination of reactive power output of multiple units and the constraints of system voltage operation. Summary of the Invention

[0003] The present invention overcomes the deficiencies of the prior art, provides a reactive power coordination control system and a control method for multiple pumped - storage units with system voltage constraints, and solves the technical problems that the reactive power output of multiple pumped - storage units cannot be reasonably coordinated and utilized, and the reactive power output of the units does not consider the constraints of the system substation voltage.

[0004] To solve the above - mentioned technical problems, the technical solution adopted by the present invention is: A reactive power coordination control system for multiple pumped - storage units with system voltage constraints, including a high - voltage bus connected to the system substation, a first voltage transformer, a first voltage collector, a high - voltage bus of the pumped - storage power station, a second voltage transformer, a second voltage collector, a control station, and a unit excitation regulator;

[0005] A first voltage transformer is connected in parallel to the high - voltage bus connected to the system substation. The secondary terminal of the first voltage transformer is connected to the input terminal of the first voltage collector through a signal acquisition line, and the output terminal of the first voltage collector is connected to the signal input terminal of the control station;

[0006] A second voltage transformer is connected in parallel to the high-voltage bus of the pumped-storage power station. The secondary terminal of the second voltage transformer is connected to the input terminal of a second voltage collector through a signal acquisition line, and the output terminal of the second voltage collector is connected to the signal input terminal of the control station;

[0007] The output terminal of the control station is connected to the input terminals of a plurality of excitation regulators of the units.

[0008] The excitation regulator of the unit is connected to the control station through a signal transmission line.

[0009] A control method for a reactive power coordination control system of multiple pumped-storage units with system voltage constraints includes:

[0010] The bus voltage of the pumped-storage power station is affected by the bus voltage of the connected system station, the voltage drop of the outgoing line, and the reactive power output of the units. The expression for the voltage drop of the outgoing line is:

[0011]

[0012] where P and Q are the active and reactive power outputs of the pumped-storage power station respectively, X and R are the reactance and resistance of the outgoing line respectively, and Us is the bus voltage of the connected system station;

[0013] The bus voltage of the pumped-storage power station is Ucs = Us + dU

[0014] From this, the coupling relationship between the reactive power Q and the bus voltage of the pumped-storage power station can be obtained as Q = f(Ucs, P);

[0015]

[0016] According to the system peak shaving demand, the pumped-storage power station needs to operate in the pumping / generating mode, the pumping / generating load is P, and the system operating voltage Us is known. Then, according to Q = f(Ucs, P), the reactive power demand of the pumped-storage power station is obtained, that is, the total reactive power to be generated in the pumping / generating mode; at this time, a primary determination of the total reactive power is required and compared with the total reactive power output capacity of the operating units. If the total capacity is less than the total demand, the operating mode needs to be adjusted to reduce the pumping / generating load of the pumped-storage units; otherwise, the reactive power load is distributed according to the capacity of the operating units, that is:

[0017]

[0018] The reactive power output after distribution is judged. If it exceeds the reactive power capacity value of the i-th (i = 1, 2,..., n, a total of n pumped-storage units) unit, the i-th unit performs reactive power distribution according to the maximum capacity value, and the surplus part is included in the deficit pool; otherwise, if it does not exceed the capacity value, it operates according to the distributed value.

[0019] For the units with reactive power margin in the above-mentioned allocation and screening, the total reactive power in the deficit pool is then re-allocated in the above manner until the reactive power in the deficit pool becomes zero.

[0020] The beneficial effects of the present invention compared with the prior art are as follows: The present invention adopts the method of connecting voltage transformers in parallel at the high-voltage bus of the access system station and the high-voltage bus of the pumped-storage power station, and uses voltage collectors to collect data from them. The collected signals are sent into the control station for information calculation, and the excitation regulator of the unit is controlled by using the determination method and process used in the present invention, so as to finally control the pumped-storage unit. A reactive power output control system for a pumped-storage power station with the system station bus voltage as a constraint is realized, and the control strategy is coordinated from the reactive power output of the unit, so as to solve the problem of mismatched reactive power output of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 It is a schematic structural diagram of the present invention.

[0023] Figure 2 It is a control flow chart of the present invention.

[0024] In the figure: 1 is the high-voltage bus of the access system station, 2 is the first voltage transformer, 3 is the first voltage collector, 4 is the high-voltage bus of the pumped-storage power station, 5 is the second voltage transformer, 6 is the second voltage collector, 7 is the control station, and 8 is the unit excitation regulator. DETAILED DESCRIPTION OF THE INVENTION

[0025] As Figure 1 and 2 shown, the multi-unit reactive power coordination control system of the present invention with system voltage constraint includes the high-voltage bus 1 of the access system station, the first voltage transformer 2, the first voltage collector 3, the high-voltage bus 4 of the pumped-storage power station, the second voltage transformer 5, the second voltage collector 6, the control station 7, and the unit excitation regulator 8;

[0026] The first voltage transformer 2 is connected in parallel to the high-voltage bus 1 of the access system station. The secondary terminal of the first voltage transformer 2 is connected to the input terminal of the first voltage collector 3 through a signal acquisition line, and the output terminal of the first voltage collector 3 is connected to the signal input terminal of the control station 7;

[0027] The second voltage transformer 5 is connected in parallel to the high-voltage bus 4 of the pumped-storage power station. The secondary terminal of the second voltage transformer 5 is connected to the input terminal of the second voltage collector 6 through a signal acquisition line, and the output terminal of the second voltage collector 6 is connected to the signal input terminal of the control station 7;

[0028] The output end of the control station 7 is connected to the input ends of a plurality of the unit excitation regulators 8.

[0029] The unit excitation regulator 8 is connected to the control station 7 through a signal transmission line.

[0030] A control method for a reactive power coordination control system of multiple pumped-storage units with system voltage constraints includes:

[0031] The bus voltage of the pumped-storage power station is affected by the bus voltage of the access system station, the voltage drop of the outgoing line, and the reactive power output of the unit. The expression for the voltage drop of the outgoing line is:

[0032]

[0033] where P and Q are the active and reactive power outputs of the pumped-storage power station respectively, X and R are the reactance and resistance of the outgoing line respectively, and Us is the bus voltage of the access system station;

[0034] The bus voltage of the pumped-storage power station is Ucs = Us + dU

[0035] From this, the coupling relationship between the reactive power Q and the bus voltage of the pumped-storage power station can be obtained as Q = f(Ucs, P);

[0036]

[0037] According to the system peak shaving demand, the pumped-storage power station needs to operate in the pumping / generating mode. The pumping / generating load is P, and the system operating voltage Us is known. Then, according to Q = f(Ucs, P), the reactive power demand of the pumped-storage power station is obtained, that is, the total reactive power to be generated in the pumping / generating mode. At this time, a primary determination of the total reactive power is required and compared with the total reactive power output capacity of the operating units. If the total capacity is less than the total demand, the operating mode needs to be adjusted to reduce the pumping / generating load of the pumped-storage units; otherwise, the reactive power load is distributed according to the capacity of the operating units, that is:

[0038]

[0039] The reactive power output after distribution is determined. If it exceeds the reactive power capacity value of the i-th (i = 1, 2,..., n, a total of n pumped-storage units) unit, the i-th unit performs reactive power distribution according to the maximum capacity value, and the surplus part is included in the deficit pool; otherwise, if it does not exceed the capacity value, it operates according to the distributed value.

[0040] For the units with remaining reactive power output after the above distribution screening, the total reactive power in the deficit pool is then redistributed in the above manner until the reactive power in the deficit pool is zero.

[0041] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Those skilled in this technology can modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field described above without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. Control method for reactive power coordination control system of multiple pumped - storage units with system voltage constraint. The specific structure of the reactive power coordination control system of multiple pumped - storage units with system voltage constraint includes the high - voltage bus of the access system station, the first voltage transformer, the first voltage collector, the high - voltage bus of the pumped - storage power station, the second voltage transformer, the second voltage collector, the control station, and the unit excitation regulator; The first voltage transformer is connected in parallel to the high - voltage bus of the access system station. The secondary terminal of the first voltage transformer is connected to the input terminal of the first voltage collector through a signal acquisition line, and the output terminal of the first voltage collector is connected to the signal input terminal of the control station; The second voltage transformer is connected in parallel to the high - voltage bus of the pumped - storage power station. The secondary terminal of the second voltage transformer is connected to the input terminal of the second voltage collector through a signal acquisition line, and the output terminal of the second voltage collector is connected to the signal input terminal of the control station; The output terminal of the control station is connected to the input terminals of multiple unit excitation regulators; The unit excitation regulator is connected to the control station through a signal transmission line; It is characterized in that, The control method for the reactive power coordination control system of multiple pumped - storage units with system voltage constraint includes: The bus voltage of the pumped - storage power station is affected by the bus voltage of the access system station, the voltage drop of the outgoing line, and the reactive power output of the unit. The expression for the voltage drop of the outgoing line is: Where P and Q are the active and reactive power outputs of the pumped - storage power station respectively, X and R are the reactance and resistance of the outgoing line respectively, and Us is the bus voltage of the access system station; The bus voltage of the pumped - storage power station is Ucs = Us + dU From this, the coupling relationship between reactive power Q and the bus voltage of the pumped - storage power station can be obtained as Q = f(Ucs, P); According to the system peak - load regulation requirements, the pumped - storage power station needs to operate in the pumping / generating mode. The pumping / generating load is P, and the system operating voltage Us is known. Then, according to Q = f(Ucs, P), the reactive power demand of the pumped - storage power station, that is, the total reactive power, is obtained. At this time, a primary determination of the total reactive power is required and compared with the total reactive power output capacity of the operating units. If the total capacity is less than the total demand, the operating mode needs to be adjusted to reduce the pumping / generating load of the pumped - storage units; otherwise, the reactive power load is distributed according to the capacity of the operating units, that is: Determine the reactive power output after distribution. If it exceeds the reactive power capacity value of the i - th (i = 1, 2,..., n, a total of n pumped - storage units) unit, the i - th unit performs reactive power distribution according to the maximum capacity value, and the surplus part is included in the deficit pool; otherwise, if it does not exceed the capacity value, it operates according to the distributed value.

2. The control method for the reactive power coordination control system of multiple pumped - storage units with system voltage constraint according to claim 1, It is characterized in that, For the units with remaining reactive power output after the above - mentioned distribution and screening, the total reactive power in the deficit pool is then redistributed in the above - mentioned manner until the reactive power in the deficit pool is zero.

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