An integrated variable speed phase condenser system

Abstract

The present invention relates to the technical field of electric power frequency modulation, and specifically to an integrated variable speed phase condenser system. An integrated variable speed phase condenser system comprises: a step-up transformer, suitable for connection with a power system line; a variable frequency converter, connected with the step-up transformer line; a variable speed phase condenser, provided with a current input end, an AC rotor and a current output end, the current input end is connected with the variable frequency converter line, the current output end is connected with the step-up transformer line, a flywheel is provided at each of the coaxial ends of the AC rotor, the variable frequency converter takes power from the step-up transformer, adjusts the power to a variable frequency low frequency AC power supply and outputs it to the current input end, and the AC rotor drives the flywheel to rotate and adjust the rotational inertia of the AC rotor during rotation, so that the power frequency generated by the variable speed phase condenser is the same as the frequency of the power system, and is input into the power system through the current output end via the step-up transformer. The present invention solves the problem that the phase condenser can only perform dynamic voltage and reactive power regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power frequency modulation, and in particular to an integrated variable speed phase regulator system. Background Art

[0002] According to the "GB40594-2021 Technical Guidelines for Power System Grid Source Coordination", when wind power and photovoltaic stations are currently connected to the system, they should have the ability to participate in the primary frequency regulation of the power system and dynamic voltage support, and they should also have the ability to support rotational inertia. To this end, when wind power and photovoltaic stations are connected to the power system, they provide voltage support capabilities by configuring static VAR generators (SVG) or static VAR compensation devices (SVC) or provide dynamic voltage support capabilities and rotational inertia support capabilities through phase shifters, and provide primary frequency regulation capabilities by configuring electrochemical energy storage, pumped storage and other energy storage power stations.

[0003] The so-called primary frequency control (PFC) refers to the control function that when the power system frequency deviates from the target frequency, the power supply automatically responds to the control system and adjusts the active output to reduce the frequency deviation.

[0004] The conventional phase modulator system is mainly composed of the phase modulator, excitation system, static frequency starting device (SFC), and step-up transformer. Its normal working process is that when the power system voltage is too high or too low, the excitation system increases or decreases the excitation current of the phase modulator to achieve high and low changes in the phase modulator stator voltage output, thereby realizing the phase modulator's regulation of the power system voltage and reactive power.

[0005] When the condenser is started, the starting current is passed through the stator and rotor of the condenser through the static frequency conversion starting device (SFC), so that the rotor of the condenser is affected by the stator current, inducing electromotive torque, dragging the condenser speed from zero to the rated speed, and then the excitation system is used to make the condenser working voltage reach the rated value. Only after meeting the grid connection adjustment requirements can it be connected to the power system. The rotor of the existing condenser consists of positive and negative stages, and the operating speed can only be synchronized with the power grid, and it has only dynamic voltage adjustment and reactive power adjustment capabilities. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the phase regulator in the prior art can only perform dynamic voltage and reactive power regulation, thereby providing an integrated variable speed phase regulator system.

[0007] In order to solve the above problems, the present invention provides an integrated variable speed phase condenser system, comprising:

[0008] A step-up transformer suitable for connection to a power system line;

[0009] A variable frequency converter connected to the step-up transformer circuit;

[0010] A variable speed phase regulator is provided with a current input terminal, an AC rotor and a current output terminal. The current input terminal is connected to a variable frequency converter circuit, the current output terminal is connected to a step-up transformer circuit, a flywheel is provided at each of the coaxial ends of the AC rotor, the variable frequency converter takes power from the step-up transformer, adjusts the power to a variable frequency low frequency AC power supply and outputs it to the current input terminal, the AC rotor drives the flywheel to rotate and adjusts the rotational inertia of the AC rotor during rotation, so that the power frequency generated by the variable speed phase regulator is the same as the frequency of the power system, and is input into the power system through the current output terminal via the step-up transformer.

[0011] Optionally, the step-up transformer has a low voltage side, and the low voltage side is connected to the variable frequency converter circuit.

[0012] Optionally, the step-up transformer is further provided with a high-voltage side, and the high-voltage side is connected to the current output end line.

[0013] Optionally, the AC power frequency is 50 Hz.

[0014] Optionally, the AC rotor has three phases: U, V, and W.

[0015] Optionally, the variable speed phase condenser further includes a stator.

[0016] Optionally, a capacitor is further included, and the capacitor is connected to the step-up transformer line.

[0017] Optionally, a reactive power compensator is also included.

[0018] The technical solution of the present invention has the following advantages:

[0019] 1. The integrated phase regulator system provided by the present invention includes: a step-up transformer, which is suitable for connecting to the power system line; a variable frequency converter, which is connected to the step-up transformer line; a variable speed phase regulator, which is provided with a current input terminal, an AC rotor and a current output terminal, wherein the current input terminal is connected to the variable frequency converter line, and the current output terminal is connected to the step-up transformer line. A flywheel is respectively provided at the coaxial ends of the AC rotor. The variable frequency converter takes power from the step-up transformer, adjusts the power to a variable frequency low-frequency AC power supply and outputs it to the current input terminal. The AC rotor drives the flywheel to rotate and adjusts the rotational inertia of the AC rotor during rotation, so that the power frequency generated by the variable speed phase regulator is the same as the frequency of the power system, and is input into the power system through the current output terminal via the step-up transformer. By adjusting the rotational inertia of the AC rotor, the frequency of the variable speed phase regulator is the same as the frequency of the power system, and it has the ability to adjust the frequency, which solves the problem of only being able to dynamically adjust the voltage and reactive power.

[0020] 2. The integrated phase regulator system provided by the present invention has a step-up transformer with a low-voltage side, and the low-voltage side is connected to the frequency converter circuit. The frequency converter takes the working power from the low-voltage side, and then adjusts the power into a low-frequency AC power with variable frequency, and transmits it to the current input terminal of the variable speed phase regulator.

[0021] 3. In the integrated phase-shifting system provided by the present invention, the step-up transformer is also provided with a high-voltage side, and the high-voltage side is connected to the current output end line, and the current output through the current output end is transmitted to the power system through the step-up transformer.

[0022] 4. The integrated phase modulator system provided by the present invention has an AC rotor with three phases, U, V, and W, and the three-phase AC rotor controls its own rotation speed.

[0023] 5. The integrated phase modulator system provided by the present invention further includes a capacitor, which is connected to the step-up transformer circuit to compensate or absorb the active power on the low-voltage side of the step-up transformer.

[0024] 6. The integrated phase-shifting system provided by the present invention also includes a reactive power compensator, through which the system is regulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of an integrated variable speed phase condenser system provided in an embodiment of the present invention;

[0027] Explanation of the reference numerals: 1. variable speed phase regulator; 2. flywheel; 3. variable frequency converter; 4. capacitor; 5. step-up transformer. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] like Figure 1 It is a specific implementation of an integrated variable speed phase condenser system, comprising: a step-up transformer 5, a variable frequency AC device and a variable speed phase condenser 1, wherein the step-up transformer 5 is suitable for connecting to a power system line. Specifically, the variable speed phase condenser 1 is a generator.

[0033] like Figure 1 As shown, the step-up transformer 5 has a low voltage side and a high voltage side, and the variable speed phase condenser 1 has a current input terminal, an AC rotor, a stator, and a current output terminal, wherein the variable frequency converter 3 is respectively connected to the low voltage side and the current input terminal line, and the high voltage side is connected to the current output terminal line. Figure 1 As shown, the AC rotor is a three-phase rotor with U, V, and W. A flywheel 2 is provided at each of the two coaxial ends of the AC rotor. A capacitor 4 is also included, wherein the capacitor 4 is connected to a step-up transformer 5 in a line.

[0034] In the primary frequency modulation process, when the power system frequency is too low and reaches the action value of the primary frequency modulation, the variable frequency converter 3 takes power from the step-up transformer 5, adjusts the power to a variable frequency low-frequency AC power supply and outputs it to the current input terminal. The AC rotor of the variable speed condenser 1 drives the flywheel 2 to reduce the speed, increases the output of active power to the power system, reduces the rotor speed of the variable speed condenser 1, and makes the actual frequency of the current output terminal of the variable speed condenser 1 the same as the power system frequency of 50Hz. The frequency of the AC power output by the variable frequency converter 3 to the AC rotor increases, making the AC power frequency induced by the stator of the variable speed condenser 1 50Hz. It should be noted that if the output active power cannot meet the primary frequency modulation value, the active power is output to the low-voltage side of the step-up transformer 5 through the capacitor 4 to meet the primary frequency modulation requirements of the variable speed condenser 1.

[0035] In order to further regulate the system, it also includes a reactive power compensator, which is connected to the power system and the phase modulator circuit respectively to cooperate with the phase modulator to adjust the reactive power output according to the power supply changes of the power system.

[0036] When the power system frequency is too high and reaches the action value of primary frequency modulation, the variable frequency converter 3 takes power from the step-up transformer 5, adjusts the power to a variable frequency low-frequency AC power supply and outputs it to the current input terminal. The AC rotor of the variable speed condenser 1 drives the flywheel 2 to increase the speed, absorbs active power from the power system, increases the rotor speed of the variable speed condenser 1, increases the mechanical frequency, and makes the actual frequency of the current output terminal of the variable speed condenser 1 the same as the power system frequency of 50Hz. The frequency of the AC power output from the variable frequency converter 3 to the AC rotor is reduced, so that the AC power frequency induced by the stator of the variable speed condenser 1 is 50Hz. It should be noted that if the output active power cannot meet the primary frequency modulation value, the active power is absorbed from the low-voltage side of the step-up transformer 5 through the capacitor 4 to meet the primary frequency modulation requirements of the variable speed condenser 1.

[0037] In a frequency modulation process, when the voltage of the power system increases, the variable frequency converter 3 reduces the AC excitation current output to the variable speed condenser 1, so that the variable speed condenser 1 absorbs reactive power from the power system and reduces the voltage of the power system; when the voltage of the power system decreases, the variable frequency converter 3 increases the AC excitation current output to the variable speed condenser 1, so that the variable speed condenser 1 sends reactive power to the power system and increases the voltage of the power system. When the reactive power provided by the variable speed condenser 1 is insufficient, the power system still lacks reactive power, and the reactive power compensator provides corresponding reactive power to the power system to maintain the voltage stability of the entire system. The power system is compared with the reactive power reference value in steady state, and a missing feedback signal is output after comparison. Reactive power is sent to the power system through the reactive power compensator, and detection is performed again. If the system is still lower than the reference value, reactive power is sent to the power system through the variable speed phase regulator 1. If the output after comparison is an excess feedback signal, reactive power is absorbed by the reactive power compensator, and detection is performed again. If the system is still higher than the reference value, the reactive power of the power system is absorbed by the variable speed phase regulator 1.

[0038] Obviously, the above embodiments are merely examples for clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from them are still within the protection scope of the invention.

Claims

1. An integrated variable speed phase condenser system, characterized in that: include: A step-up transformer (5) adapted to be connected to a power system line; A variable frequency converter (3) connected to the step-up transformer (5); A variable speed phase regulator (1), the variable speed phase regulator (1) being provided with a current input terminal, an AC rotor and a current output terminal, the current input terminal being connected to a variable frequency converter (3) circuit, the current output terminal being connected to a step-up transformer (5) circuit, a flywheel (2) being provided at each of the coaxial ends of the AC rotor, the variable frequency converter (3) taking power from the step-up transformer (5), adjusting the power to a variable frequency low frequency AC power supply and outputting it to the current input terminal, the AC rotor driving the flywheel (2) to rotate and adjusting the rotational inertia of the AC rotor during rotation, so that the power frequency generated by the variable speed phase regulator (1) is the same as the frequency of the power system, and is input into the power system through the current output terminal via the step-up transformer (5); It also includes a capacitor (4), which is connected to the step-up transformer (5).

2. The integrated variable speed phase condenser system according to claim 1, characterized in that: The step-up transformer (5) has a low-voltage side, and the low-voltage side is connected to the frequency converter (3) line.

3. The integrated variable speed phase condenser system according to claim 2, characterized in that: The step-up transformer (5) is also provided with a high-voltage side, and the high-voltage side is connected to the current output end line.

4. The integrated variable speed phase condenser system according to claim 1, characterized in that: The frequency of the AC power supply is 50 Hz.

5. The integrated variable speed phase condenser system according to claim 4, characterized in that: The AC rotor has three phases: U, V, and W.

6. The integrated variable speed phase condenser system according to claim 5, characterized in that: The variable speed phase condenser (1) also includes a stator.

7. The integrated variable speed phase condenser system according to claim 1, characterized in that: Also includes reactive power compensator.

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