Direct current side control system and method of static synchronous phase modifier

Abstract

The invention provides a DC side control system and method for a static synchronous phase modifier, and the method comprises the steps: confirming that the AC side of the static synchronous phase modifier is unlocked, and setting a first DC side voltage set value; comparing the direct-current side voltage sampling value with a first direct-current side voltage set value, and when the direct-current side voltage sampling value is equal to the first direct-current side voltage set value, closing a direct-current side circuit breaker; setting a second direct current side voltage set value, wherein the second direct current side set value is greater than the first direct current side set value; and when the second direct-current side set value is equal to the residual voltage sum of the energy storage modules, the direct-current side is unlocked, and the direct-current side of the static synchronous phase modifier is switched on online. According to the direct current side control method of the static synchronous phase modifier, the operation mode of the static synchronous phase modifier can be automatically switched according to the requirement of a power grid for the static synchronous phase modifier in combination with the operation state of the static synchronous phase modifier.

Description

Technical Field

[0001] The present application relates to the field of power electronic control technology, and in particular to a DC side control system and method for a static synchronous phase condenser. Background Art

[0002] New energy stations are usually equipped with static var generators (SVG) to provide reactive power and voltage support for the system. Most of these devices operate in the grid-following (GFL) mode, which can be equivalent to a controlled current source based on a phase-locked loop. Under weak grid conditions, they are prone to resonance with grid impedance and other problems, which can cause system instability in severe cases. In this context, two main technical routes have been derived: one is to add a grid-forming (GFM) control algorithm to the control strategy of traditional SVG, so that SVG simulates the operating characteristics of a synchronous generator and operates in a self-synchronous voltage source mode to improve its adaptability to weak grids; the other is to use an MMC (modular multilevel converter, MMC) rectifier topology on the valve side, and connect an energy storage device between the positive and negative poles on the DC side. This is the main topology of a static self-synchronous compensator (SSC). Among them, a single energy storage module is a half-bridge structure or a full-bridge structure, and the DC side can be a supercapacitor cluster, a lithium battery cluster, or a hybrid of the two. Therefore, SSC not only has the voltage and reactive power support capabilities of conventional SVG, but can also provide frequency and inertia support to the power grid with the help of DC side energy storage devices.

[0003] In terms of operation mode, SSC can either be operated with a DC side energy storage device in a grid-following or grid-building mode, or it can disconnect the DC side and operate as two sets of SVG equipment in a grid-following or grid-building mode. Therefore, how to realize the online commissioning and decommissioning of DC side energy storage units is a key issue that needs to be solved for SSC to achieve large-scale engineering applications. Summary of the invention

[0004] The present application provides a DC side control system and method for a static synchronous condenser to solve the problem of how to online switch in and out of a DC side energy storage unit to achieve large-scale engineering application of SSC.

[0005] In order to solve the above technical problems, the present application provides a DC side control method for a static synchronous phase condenser, including: confirming that the AC side of the static synchronous phase condenser has been unlocked and is running, and the DC side meets the ready condition, and setting a first DC side voltage setting value; comparing the DC side voltage sampling value with the first DC side voltage setting value, and when the DC side voltage sampling value is equal to the first DC side voltage setting value, the DC side circuit breaker is closed; setting a second DC side voltage setting value, and the second DC side voltage setting value is greater than the first DC side voltage setting value; when the second DC side voltage setting value is equal to the sum of the residual voltages of each energy storage module, the DC side is unlocked, and after the DC side voltage continues to charge to the rated working value, the DC side of the static synchronous phase condenser is put online.

[0006] Furthermore, the DC side control method of the static synchronous condenser also includes: confirming that the AC side of the static synchronous condenser has been unlocked and in operation, and the DC side is in an unlocked operation state; the energy storage module receives a drive locking instruction and executes a drive pulse blocking; after confirming that the DC side has been locked, compare the DC side voltage sampling value with the third DC side voltage setting value, and when the DC side voltage sampling value is lower than the third DC side voltage setting value, it is determined that the DC side voltage has been adjusted; compare the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the DC side current setting value, it is determined that the DC current has dropped to zero. When both the DC side voltage has been adjusted and the DC side current has dropped to zero are met, the DC side circuit breaker is opened to complete the online exit of the DC side of the static synchronous condenser.

[0007] Furthermore, in the DC side control method of the static synchronous phase condenser, the DC side meets the ready conditions including: the DC side grounding switches are all in the open position, the isolation switches are all in the closed position, the AC side main circuit breakers are all in the open position, and each energy storage module is in a locked state.

[0008] Furthermore, in the DC side control method of the static synchronous phase condenser, the DC side voltage sampling value is compared with the first DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the first DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has dropped to the first DC side voltage setting value.

[0009] Furthermore, in the DC side control method of the static synchronous phase condenser, the DC side voltage sampling value is compared with the third DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the third DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has been adjusted.

[0010] Furthermore, in the DC side control method of the static synchronous phase regulator, the DC side current sampling value is compared with the DC side current setting value through a hysteresis comparator. When the DC side current sampling value is lower than the DC side current setting value, a high level 1 is output to determine that the DC current has dropped to zero.

[0011] The present invention also provides a DC side control system of a static synchronous condenser, comprising: a static synchronous condenser main controller, the static synchronous condenser main controller confirms that the AC side of the static synchronous condenser has been unlocked and is running, and the DC side meets the ready condition, and the static synchronous condenser main controller sets a first DC side voltage setting value; compares the DC side voltage sampling value with the first DC side voltage setting value, when the DC side voltage sampling value is equal to the first DC side voltage setting value, the static synchronous condenser main controller issues a DC side circuit breaker closing instruction to close the DC side circuit breaker; sets a second DC side voltage setting value, the second DC side voltage setting value is greater than the first DC side voltage setting value; a DC side controller, when the second DC side voltage setting value is equal to the sum of the residual voltages of each energy storage module, the static synchronous condenser main controller issues a drive unlocking instruction to the DC side controller; an energy storage module controller, the DC side controller forwards the drive unlocking instruction to each energy storage module controller to execute pulse unlocking, and the DC side of the static synchronous condenser is put online.

[0012] Furthermore, the DC side control system of the static synchronous condenser also includes the static synchronous condenser main controller confirming that the AC side of the static synchronous condenser has been unlocked and the DC side is in the unlocked operation state; the static synchronous condenser main controller sends the energy storage module drive locking instruction to the DC side controller, and the DC side controller forwards it to each of the energy storage module controllers to execute the drive pulse blocking; after the static synchronous condenser main controller confirms that the DC side has been locked, it sets the third DC side voltage setting value; compares the DC side voltage sampling value with the third DC side voltage setting value, and when the DC side voltage sampling value is lower than the third DC side voltage setting value, it is determined that the DC side voltage has been adjusted; compares the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the DC side current setting value, it is determined that the DC current has dropped to zero. When both the DC side voltage has been adjusted and the DC side current has dropped to zero are satisfied, the static synchronous condenser main controller sends the DC side circuit breaker closing instruction to open the DC side circuit breaker, completing the DC side online exit of the static synchronous condenser.

[0013] Furthermore, in the DC side control system of the static synchronous condenser, the DC side meets the ready conditions including: the DC side grounding switches are all in the open position, the isolation switches are all in the closed position, the main circuit breakers are all in the open position, and each energy storage module is in a locked state.

[0014] Furthermore, in the DC side control system of the static synchronous phase condenser, a hysteresis comparator is used to compare the DC side voltage sampling value with the first DC side voltage setting value. When the DC side voltage sampling value is lower than the first DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has dropped to the first DC side voltage setting value.

[0015] Furthermore, in the DC side control system of the static synchronous phase condenser, a hysteresis comparator is used to compare the DC side voltage sampling value with the third DC side voltage setting value. When the DC side voltage sampling value is lower than the third DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has been adjusted.

[0016] Furthermore, in the DC side control system of the static synchronous phase regulator, the DC side current sampling value is compared with the DC side current setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the DC side current setting value, a high level 1 is output to determine that the DC current has dropped to zero.

[0017] The DC side control method of the static synchronous condenser provided by the present invention can automatically switch the operating mode of the static synchronous condenser equipment according to the demand of the power grid for the static synchronous condenser equipment and the operating status of the static synchronous condenser itself; in conjunction with the adjustment of the overall control strategy of the system, the static synchronous condenser can be flexibly adapted to different power grid conditions and maximize its support and regulation capabilities for the power grid in the most efficient manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of a DC side input process in a DC side control method of a static synchronous condenser provided in an embodiment of the present invention; Figure 2 A schematic diagram of a DC side exit process in a DC side control method of a static synchronous condenser provided in an embodiment of the present invention; Figure 3 A schematic diagram of the action logic of the hysteresis comparator provided in an embodiment of the present invention; Figure 4 A schematic diagram of the control structure of a DC side switching control system of a static synchronous condenser provided in an embodiment of the present invention; Figure 5 A schematic diagram of the main circuit topology structure of a static synchronous condenser provided in an embodiment of the present invention; Figure 6 A schematic diagram of the structure of a DC-side energy storage module of a static synchronous condenser provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In the description of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In the description of this application, 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, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0024] Figure 1A schematic diagram of the DC side input process in the DC side control method of the static synchronous condenser provided in an embodiment of the present invention. Referring to 1, confirm that the AC side of the static synchronous condenser has been unlocked and is running, and the DC side meets the ready condition, set the first DC side voltage setting value; compare the DC side voltage sampling value with the first DC side voltage setting value, and when the DC side voltage sampling value is equal to the first DC side voltage setting value, close the DC side circuit breaker; set the second DC side voltage setting value, and the second DC side voltage setting value is greater than the first DC side voltage setting value; when the second DC side voltage setting value is equal to the sum of the residual voltages of each energy storage module, the DC side is unlocked, and after the total DC side voltage continues to charge to the rated value, the DC side of the static synchronous condenser is online.

[0025] In the embodiment of the present invention, the static synchronous phase condenser main controller first controls the SSC AC side to be connected to the grid and then unlocked, and two sets of static VAR generators are operated in parallel, the DC side circuit breaker is in the disconnected state, and the DC side voltage between the neutral points of the two sets of static VAR generators is controlled at 0.4pu.

[0026] The main controller of the stop-type synchronous condenser needs to confirm the current operating status, that is, the DC side grounding switches are in the open position, the isolation switches are in the closed position, the main circuit breakers are in the open position, and all energy storage modules are in the locked state. Figure 1 , if the AC side is unlocked and the DC side meets the above-mentioned ready conditions, the main controller of the static synchronous phase condenser executes the DC side voltage reduction instruction and sets the DC side voltage control instruction to 0; in the embodiment of the present invention, the DC side voltage sampling value is compared with the first DC side voltage setting value 0 through the hysteresis comparator, Figure 3 Schematic diagram of the operation logic of the hysteresis comparator provided by the embodiment of the present invention. Figure 3 The hysteresis comparator of the embodiment of the present invention includes two parameters: threshold voltage and hysteresis width , when the input signal is less than the threshold voltage , then the output is high level 1, the input signal is greater than the threshold voltage and hysteresis width The output is low level 0; in the embodiment of the present invention, the threshold voltage 0.01pu, hysteresis width When the DC side voltage sampling value is lower than 0.01pu, it outputs high level 1, judging that the DC side voltage has dropped to 0 (within the dead zone) within the allowable error range.

[0027] The main controller of the static synchronous condenser sends a closing command for the DC side circuit breaker, and the corresponding operating mechanism executes the closing. After the main controller of the static synchronous condenser confirms that the DC side circuit breaker is in the closed position, the DC voltage control command is increased to the second DC side voltage setting value 1.0pu at a set slope. Since the DC side energy storage module is still in a locked state at this time, and there is an anti-parallel diode, the energy storage module is in a stage where it can be charged but not discharged. There is residual voltage in the energy storage module. If the actual DC side voltage has not increased to a level greater than the total residual voltage of the energy storage module in the initial stage of the boost, the energy storage module cannot be charged at this time. As the actual DC side voltage gradually increases with the control command, it will gradually approach the total residual voltage of the energy storage module. When the two are equal within the allowable error range (within the dead zone range), the main controller of the static synchronous condenser determines that the DC side unlocking condition has been met. The main controller of the static synchronous condenser sends a drive unlocking command to the DC side controller, and the DC side controller forwards it to each energy storage module controller to execute pulse unlocking. The DC side voltage continues to charge to the rated working value, completing the online input of the DC side of the static synchronous condenser.

[0028] Figure 2 A schematic diagram of the DC side exit process in the DC side control method of the static synchronous condenser provided in the embodiment of the present invention. Referring to 2, confirm that the AC side of the static synchronous condenser has been unlocked and in operation, and the DC side is in the unlocked operation state; the energy storage module receives the drive locking instruction and executes the drive pulse blocking; after confirming that the DC side has been locked, set the third DC side voltage setting value; compare the DC side voltage sampling value with the third DC side voltage setting value, and when the DC side voltage sampling value is lower than the third DC side voltage setting value, determine that the DC side voltage has been adjusted; compare the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the current setting value, determine that the DC current has dropped to zero, and the DC side circuit breaker is opened to complete the online exit of the DC side of the static synchronous condenser.

[0029] In the embodiment of the present invention, each module controller confirms that the pulse has been blocked, and uploads a locked state signal to the static synchronous condenser main controller through the DC side controller. After the static synchronous condenser main controller confirms that the DC side has been locked, the DC voltage control instruction is set to 0.45pu; the actual DC voltage gradually decreases from the rated working value, and the DC side voltage sampling value is compared with the set value 0.45pu through the hysteresis comparator, and the threshold voltage 0.45pu, hysteresis width When the actual DC side voltage is lower than 0.45pu, the output is high level 1, judging that the DC side voltage has been adjusted within the allowable error range; because the DC side is locked, the energy storage module cannot be discharged. When the DC side voltage is lower than the residual voltage of each energy storage module, the energy storage module cannot be charged, so the DC current will also be 0. Figure 3 , compare the DC side current with the set value 0.01pu, the threshold current 0.01pu, hysteresis width When the actual DC side current is lower than 0.01pu, it outputs high level 1, judging that the DC current has dropped to 0 within the allowable error range. When the DC side voltage has been adjusted and the DC side current has dropped to zero, the main controller of the static synchronous condenser sends a DC side circuit breaker opening command, and the corresponding operating mechanism performs the opening; the main controller of the static synchronous condenser confirms that the DC side circuit breaker is in the open position, and completes the DC side online exit of the static synchronous condenser.

[0030] Before the DC side of the static synchronous condenser is put into operation (or after it is withdrawn), the system operates in static VAR generator (SVG) mode, the DC side circuit breaker is in the disconnected state, and the DC side voltage between the neutral points of the two sets of SVG can be controlled at other values ​​except 0.4pu. This value mainly varies with the different MMC (modular multilevel converter) valve control strategies.

[0031] The DC side control method of the static synchronous condenser provided by the present invention can automatically switch the operating mode of the static synchronous condenser equipment according to the demand of the power grid for the static synchronous condenser equipment and the operating status of the static synchronous condenser itself; in conjunction with the adjustment of the overall control strategy of the system, the static synchronous condenser can be flexibly adapted to different power grid conditions and maximize its support and regulation capabilities for the power grid in the most efficient manner.

[0032] The present invention also provides a DC side control system of a static synchronous condenser, comprising: a static synchronous condenser main controller, the static synchronous condenser main controller confirms that the AC side of the static synchronous condenser has been unlocked and is running, and the DC side meets the ready condition, and the static synchronous condenser main controller sets a first DC side voltage setting value; compares the DC side voltage sampling value with the first DC side voltage setting value, when the DC side voltage sampling value is equal to the first DC side voltage setting value, the static synchronous condenser main controller issues a DC side circuit breaker closing instruction to close the DC side circuit breaker; sets a second DC side voltage setting value, the second DC side setting value is greater than the first DC side setting value; a DC side controller, when the second DC side setting value is equal to the sum of the residual voltages of each energy storage module, the static synchronous condenser main controller issues a drive unlocking instruction to the DC side controller; an energy storage module controller, the DC side controller forwards the drive unlocking instruction to each energy storage module controller to execute pulse unlocking, and the DC side of the static synchronous condenser is put online.

[0033] The DC side control system of the static synchronous condenser also includes the static synchronous condenser main controller confirming that the AC side of the static synchronous condenser has been unlocked and the DC side is in the unlocked operation state; the static synchronous condenser main controller sends the energy storage module drive locking instruction to the DC side controller, and the DC side controller forwards it to each of the energy storage module controllers to execute the drive pulse blocking; after the static synchronous condenser main controller confirms that the DC side has been locked, it sets the third DC side voltage setting value; compares the DC side voltage sampling value with the third DC side voltage setting value, and when the DC side voltage sampling value is lower than the third DC side voltage setting value, it is determined that the DC side voltage has been adjusted; compares the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the DC side current setting value, it is determined that the DC current has dropped to zero. When both the DC side voltage has been adjusted and the DC side current has dropped to zero are met, the static synchronous condenser main controller sends the DC side circuit breaker closing instruction, and the DC side circuit breaker is opened to complete the DC side online exit of the static synchronous condenser.

[0034] Figure 4 This is a schematic diagram of the control structure of the DC side switching control system of the static synchronous condenser provided by the embodiment of the present invention. Figure 4In order to realize the online switching on and off of the DC side of the static synchronous condenser, the DC side switching on and off control system of the static synchronous condenser includes the static synchronous condenser main controller, the DC side sub-controller and the energy storage module controller. The static synchronous condenser main controller is mainly responsible for the implementation of system-level control and protection strategies, including DC voltage closed-loop control, operation of each switch in the main circuit, etc.; the DC side controller, as the interface between the energy storage module and the static synchronous condenser main controller, is mainly responsible for sending the analog quantity and state quantity information of each energy storage module to the static synchronous condenser main controller, and sending the unlocking instruction from the main controller to each energy storage module controller, etc. The energy storage module controller corresponds to the energy storage module on the DC side one by one, and is responsible for the drive control and protection of the energy storage module monomer.

[0035] Figure 5 A schematic diagram of the main circuit topology structure of a static synchronous condenser provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the DC side energy storage module structure of a static synchronous condenser provided in an embodiment of the present invention. Figure 5 and Figure 6 ,in Figure 6 The energy storage structure modules shown may be (a) lithium battery half-bridge module, (b) supercapacitor half-bridge module, (c) lithium battery full-bridge module, (d) supercapacitor full-bridge module. In the embodiment of the present invention, the valve side adopts MMC (modular multilevel converter) rectification topology.

[0036] Obviously, the above embodiments are merely examples for the purpose of 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 therefrom are still within the scope of protection created by this application.

Claims

1. A DC side control method for a static synchronous condenser, characterized in that: include: Confirm that the AC side of the static synchronous condenser has been unlocked and is running, and that the DC side meets the ready conditions, and set the first DC side voltage setting value; Comparing the DC side voltage sampling value with the first DC side voltage setting value, when the DC side voltage sampling value is equal to the first DC side voltage setting value, closing the DC side circuit breaker; Setting a second DC link voltage setting value, wherein the second DC link voltage setting value is greater than the first DC link voltage setting value; When the second DC side voltage setting value is equal to the sum of the residual voltages of the energy storage modules, the DC side is unlocked, and the total DC side voltage continues to charge to the rated value, completing the online input of the DC side of the static synchronous phase regulator.

2. The DC side control method of a static synchronous condenser according to claim 1, characterized in that: Also includes: Confirm that the AC side of the static synchronous condenser has been unlocked and the DC side is in unlocked operation; The energy storage module receives the drive blocking instruction and executes the drive pulse blocking; After confirming that the DC side has been locked, comparing the DC side voltage sampling value with the third DC side voltage setting value, when the DC side voltage sampling value is lower than the third DC side voltage setting value, determining that the DC side voltage has been adjusted; Comparing the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the DC side current setting value, determining that the DC current has dropped to zero; When both the DC side voltage adjustment and the DC side current drop to zero are met, the DC side circuit breaker is opened to complete the online exit of the DC side of the static synchronous phase regulator.

3. The DC side control method of a static synchronous condenser according to claim 1, characterized in that: The DC side meets the ready conditions including: the DC side grounding switches are all in the open position, the isolation switches are all in the closed position, the AC side main circuit breakers are all in the open position, and all energy storage modules are in the locked state.

4. The DC side control method of a static synchronous condenser according to claim 1, characterized in that: The DC side voltage sampling value is compared with the first DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the first DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has dropped to the first DC side voltage setting value.

5. The DC side control method of a static synchronous condenser according to claim 2, characterized in that: The DC side voltage sampling value is compared with the third DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the third DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has been adjusted.

6. The DC side control method of a static synchronous condenser according to claim 2, characterized in that: The DC side current sampling value is compared with the DC side current setting value through the hysteresis comparator. When the DC side current sampling value is lower than the DC side current setting value, a high level 1 is output to determine that the DC current has dropped to zero.

7. A DC side control system of a static synchronous condenser, characterized in that: include: A static synchronous condenser main controller, wherein the static synchronous condenser main controller confirms that the AC side of the static synchronous condenser has been unlocked and is running, and the DC side meets the ready condition, and the static synchronous condenser main controller sets a first DC side voltage setting value; Comparing the DC side voltage sampling value with the first DC side voltage setting value, when the DC side voltage sampling value is equal to the first DC side voltage setting value, the static synchronous phase condenser main controller issues a DC side circuit breaker closing instruction to close the DC side circuit breaker; Setting a second DC link voltage setting value, wherein the second DC link voltage setting value is greater than the first DC link voltage setting value; The DC side controller, when the second DC side voltage setting value is equal to the sum of the residual voltages of the energy storage modules, the static synchronous phase condenser main controller sends a drive unlocking instruction to the DC side controller; The energy storage module controller, the DC side controller forwards the drive unlocking instruction to each energy storage module controller to execute pulse unlocking, and the DC side of the static synchronous phase regulator is put into online operation.

8. The DC side control system of the static synchronous condenser according to claim 7, characterized in that: Also includes: The main controller of the static synchronous condenser confirms that the AC side of the static synchronous condenser has been unlocked and operated, and the DC side is in an unlocked operation state; The main controller of the static synchronous condenser sends an energy storage module drive blocking instruction to the DC side controller, and the DC side controller forwards it to each of the energy storage module controllers to execute drive pulse blocking; After the main controller of the static synchronous condenser confirms that the DC side has been locked, the DC side voltage sampling value is compared with the third DC side voltage setting value. When the DC side voltage sampling value is lower than the third DC side voltage setting value, it is determined that the DC side voltage has been adjusted. Comparing the DC side current sampling value with the DC side current setting value, and when the DC side current sampling value is lower than the DC side current setting value, determining that the DC side current has dropped to zero; When both the DC side voltage adjustment and the DC side current reduction to zero are satisfied, the static synchronous phase condenser main controller sends a DC side circuit breaker closing command to open the DC side circuit breaker, thus completing the DC side online exit of the static synchronous phase condenser.

9. The DC side control system of the static synchronous condenser according to claim 7, characterized in that: The DC side meets the ready conditions including: the DC side grounding switches are all in the open position, the isolation switches are all in the closed position, the main circuit breakers are all in the open position, and all energy storage modules are in the locked state.

10. The DC side control system of the static synchronous condenser according to claim 7, characterized in that: The DC side voltage sampling value is compared with the first DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the first DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has dropped to the first DC side voltage setting value.

11. The DC side control system of the static synchronous condenser according to claim 8, characterized in that: The DC side voltage sampling value is compared with the third DC side voltage setting value through a hysteresis comparator. When the DC side voltage sampling value is lower than the third DC side voltage setting value, a high level 1 is output to determine that the DC side voltage has been adjusted.

12. The DC side control system of the static synchronous condenser according to claim 8, characterized in that: The DC side current sampling value is compared with the DC side current setting value through the hysteresis comparator. When the DC side voltage sampling value is lower than the DC side current setting value, a high level 1 is output to determine that the DC current has dropped to zero.

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