Supercapacitor energy storage management system, charging method and device in static synchronous condenser

Abstract

The present application provides a supercapacitor energy storage management system, a charging method, and a device in a static synchronous condenser, and relates to the field of static synchronous condensers. The supercapacitor energy storage management system includes a power unit, a high-voltage box, and a supercapacitor unit that are electrically connected in sequence; the power unit is used to realize power conversion during the charging and discharging process of the supercapacitor; the high-voltage box is used to realize the electrical connection between the supercapacitor unit and the power unit, and a switching power supply is provided in the high-voltage box. The power supply point of the switching power supply includes a first power supply point, and the first power supply point is connected to the positive output terminal of the power unit. When the supercapacitor is in a charging state, the switching power supply supplies power to the first capacitor management unit through the first power supply point; the supercapacitor unit includes a supercapacitor and a first capacitor management unit, and the first capacitor management unit draws power from the switching power supply. The first capacitor management unit is used to monitor the supercapacitor in the charging and operating state. The present application can monitor the complete charging process of the supercapacitor.

Description

Technical Field

[0001] The present application relates to the field of static synchronous condensers, and in particular to an over-capacity energy storage management system, a charging method, and an over-capacity energy storage management system for static synchronous condensers. Background Art

[0002] With the increasing use of power electronic converters in power systems, the physical form of new power systems is gradually shifting from traditional mechanical electromagnetic systems dominated by synchronous generators to hybrid systems dominated by power electronics and synchronous generators, including power semiconductors and ferromagnetic components. As the proportion of converters in power systems increases, the system's equivalent inertia will be significantly reduced, and frequency stability will deteriorate, potentially leading to frequency stability incidents. This is particularly true in power grids with weak system strength and low physical inertia. This situation seriously affects the safe connection of renewable energy sources to the grid, significantly restricting their absorption capacity.

[0003] Traditional static var generators (SVGs) offer both reactive power compensation and voltage support capabilities, but they carry the risk of voltage overcompensation during AC system fault conditions and cannot fully meet the demand for improving the stability of renewable energy grid integration in weak grid conditions. Synchronous condensers have garnered widespread industry attention over the past decade due to their unique advantages in enhancing system inertia support and improving frequency and voltage characteristics. However, they are subject to significant challenges, such as high cost, complex systems, difficult maintenance, and challenging site selection. With the continuous advancement of power electronics and control technologies, the concept of grid-connected SVGs has emerged, commonly referred to in the industry as static synchronous condensers.

[0004] Static synchronous condensers (SSCs) offer both inertia support and transient voltage support capabilities, effectively improving system voltage stability. Their design typically incorporates an energy storage unit (ESM) in a traditional SVG architecture. These units are typically supercapacitors or batteries, and each unit requires a corresponding Capacitor Management System (CMS). In conventional designs, the EMS's operating power is typically drawn directly from the EMS it manages. This energy draw method is effective for battery energy storage systems, as batteries typically never fully deplete to zero. However, supercapacitors lack this characteristic and, when unused for extended periods, self-discharge causes their voltage to drop to zero. Therefore, when the supercapacitor voltage falls below a certain threshold due to self-discharge, the EMS becomes inoperable due to the low voltage. During initial startup, when pre-charging the supercapacitor, conventional designs (for example, directly connecting the supercapacitor to the EMS and charging it via an external large resistor in the main circuit) prevent the EMS from starting up if the supercapacitor is initially empty or undercharged, leading to an unknown operating status. This method leaves the supercapacitors unmonitored for a period of time during the initial charging phase, which is extremely dangerous for high-voltage systems. Considering that a static synchronous condenser system may be equipped with tens of thousands of supercapacitors, this uncontrolled state can easily pose a safety hazard. Furthermore, static synchronous condensers are often used in high-voltage systems such as 10kV and 35kV. Using an isolation transformer to power their energy storage management system would greatly complicate the system, significantly increasing its size and cost. Conventional low-voltage isolated power supply methods are also generally unsuitable. Summary of the Invention

[0005] This application provides a supercapacitor energy storage management system, charging method, and device for a static synchronous condenser, addressing the prior art issue of being unable to monitor the supercapacitor's charging process when the supercapacitor's voltage is low. Furthermore, this application eliminates the need for an isolation transformer to power the supercapacitor energy storage management system, resulting in a simple structure, low cost, and no need for conventional low-voltage isolated power supply, making it highly applicable.

[0006] The present application provides a supercapacitor energy storage management system in a static synchronous condenser, comprising a power unit, a high-voltage box, and a supercapacitor unit electrically connected in sequence;

[0007] The power unit is used to realize power conversion during the charging and discharging process of the supercapacitor in the supercapacitor unit;

[0008] The high-voltage box is used to realize the electrical connection between the supercapacitor unit and the power unit. A switching power supply is provided in the high-voltage box. The power supply point of the switching power supply includes a first power supply point. The first power supply point is connected to the positive output terminal of the power unit. When the supercapacitor is in the charging state, the switching power supply supplies power to the first capacitance management unit in the supercapacitor unit through the first power supply point.

[0009] The supercapacitor unit is used to provide active power support for the static synchronous condenser. The supercapacitor unit includes a supercapacitor and a first capacitance management unit. The supercapacitor is electrically connected to the first capacitance management unit. The first capacitance management unit draws power from the switching power supply. The first capacitance management unit is used to monitor the supercapacitor in the charging and operating state.

[0010] According to the supercapacitor energy storage management system provided by the present application, a second capacitance management unit is further provided in the high-voltage box, and the second capacitance management unit is electrically connected to the first capacitance management unit;

[0011] The second capacitance management unit is used to monitor the supercapacitor in a charging and operating state and the first capacitance management unit in an operating state.

[0012] According to the supercapacitor energy storage management system provided by the present application, a supercapacitor charging circuit is further provided in the high-voltage box, and the supercapacitor charging circuit is electrically connected to the positive output terminal of the power unit and the positive input terminal of the switching power supply, respectively. The supercapacitor charging circuit is located after the first power supply point, and the power unit includes a DC bus capacitor;

[0013] The charging circuit of the supercapacitor is used to charge the supercapacitor when the voltage across the DC bus capacitor is greater than or equal to a first voltage threshold and the voltage across the supercapacitor is lower than a second voltage threshold.

[0014] According to the supercapacitor energy storage management system provided by the present application, the power supply point of the switching power supply further includes a second power supply point, the second power supply point is located after the charging circuit of the supercapacitor, and a diode module is further provided in the high-voltage box, the anode of the diode module is electrically connected to the output end of the charging circuit of the supercapacitor, the output end of the diode module is connected to the positive input end of the switching power supply, and the input end of the diode module is connected to the first power supply point and the second power supply point;

[0015] The diode module is used to control the switching power supply to obtain power from the first power point, or to obtain power from the second power point.

[0016] According to the supercapacitor energy storage management system provided by the present application, the diode module includes a first diode and a second diode, the first diode and the second diode are connected to a common cathode, the cathode of the first diode or the second diode is connected to the positive input terminal of the switching power supply, the anode of the first diode is connected to the first power point, and the anode of the second diode is connected to the second power point;

[0017] The first diode is used to supply power to the switching power supply through the first power point;

[0018] The second diode is used to supply power to the switching power supply through the second power supply point.

[0019] The present application also provides a super-capacitor charging method based on the super-capacitor energy storage management system in the above-mentioned static synchronous condenser, comprising:

[0020] When it is determined that the supercapacitor is to be charged, controlling the switching power supply to enter an operating state through the first power point;

[0021] When the switching power supply is in an operating state, controlling the first capacitance management unit to enter an operating state;

[0022] When the first capacitance management unit is in an operating state, the supercapacitor is controlled to enter a charging state.

[0023] According to the supercapacitor charging method provided by the present application, after controlling the switching power supply to enter the operating state, the method further includes:

[0024] When the switching power supply is in an operating state, controlling the second capacitance management unit to enter an operating state;

[0025] When the first capacitance management unit is in the running state, controlling the supercapacitor to enter the charging state includes:

[0026] When the first capacitance management unit is in an operating state, if the second capacitance management unit is in an operating state, the supercapacitor is controlled to enter a charging state.

[0027] According to the supercapacitor charging method provided by the present application, after controlling the supercapacitor to enter a charging state, the method further includes:

[0028] The diode module is used to control the switching power supply to obtain power from the first power point or the second power point.

[0029] According to the supercapacitor charging method provided by the present application, after controlling the supercapacitor to enter a charging state, the method further includes:

[0030] When the voltage difference between the voltage across the supercapacitor and the voltage across the DC bus capacitor is within a preset voltage difference range, the supercapacitor is controlled to exit the charging state.

[0031] The present application also provides a supercapacitor charging method based on the supercapacitor energy storage management system in the above-mentioned static synchronous condenser, which is applied to a controller in the static synchronous condenser, wherein the controller is electrically connected to the power unit. The supercapacitor charging method includes:

[0032] a first control module, configured to control the switching power supply to enter an operating state through the first power point when it is determined that the supercapacitor is to be charged;

[0033] a second control module, configured to control the first capacitance management unit to enter an operating state when the switching power supply is in an operating state;

[0034] The third control module is used to control the supercapacitor to enter a charging state when the first capacitance management unit is in an operating state.

[0035] The present application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a super-capacitor charging method for a static synchronous condenser as described above is implemented.

[0036] The present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the super-capacity charging method of the super-capacity energy storage management system in the static synchronous condenser as described in any one of the above is implemented.

[0037] The present application also provides a computer program product, including a computer program, which, when executed by a processor, implements a super-capacity charging method for a super-capacity energy storage management system in a static synchronous condenser as described in any one of the above.

[0038] In this application, when the supercapacitor needs to be charged, the switching power supply can draw power from the first power point to power the first capacity management unit, allowing the first capacity management unit to remain in an operational state (i.e., working state). This eliminates the situation in the related art where the supercapacitor is unmonitored for a period of time while charging the supercapacitor, thus avoiding the potential safety hazards caused by this uncontrolled state. Furthermore, this application eliminates the need for an isolation transformer to power the supercapacitor energy storage management system, resulting in a simple structure, low cost, and no need for conventional low-voltage isolated power supply, making it highly applicable. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 This is a structural diagram of a super-capacitor energy storage management system in a static synchronous condenser according to an embodiment of the present application;

[0041] Figure 2 This is a schematic diagram of the principle of a high-voltage box shown in one embodiment of the present application;

[0042] Figure 3 This is a schematic diagram of a stationary synchronous condenser using a star connection method according to an embodiment of the present application;

[0043] Figure 4 This is a schematic diagram of a stationary synchronous condenser using a delta connection method according to an embodiment of the present application;

[0044] Figure 5 This is a flow chart of an overcapacity charging method of an overcapacity energy storage management system in a static synchronous condenser shown in one embodiment of the present application;

[0045] Figure 6 This is a structural block diagram of a supercapacitor charging device for a static synchronous condenser according to an embodiment of the present application;

[0046] Figure 7 This is a schematic diagram of the physical structure of an electronic device shown in an embodiment of the present application. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only 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.

[0048] This application first provides a super-capacitor energy storage management system in a static synchronous condenser, the structure of which is as follows: Figure 1 shown. Figure 1 1 is a structural diagram of a super-capacitor energy storage management system in a static synchronous condenser according to an embodiment of the present application.

[0049] Reference Figure 1The supercapacitor energy storage management system of the present application includes a power unit, a high-voltage box and a supercapacitor unit electrically connected in sequence.

[0050] In the present application, the positive and negative poles of the power unit are connected to the positive and negative poles of the high-voltage box respectively, and the positive and negative poles of the high-voltage box are connected to the positive and negative poles of the supercapacitor unit respectively.

[0051] In the present application, the power unit is used to implement power conversion during the charging and discharging process of the supercapacitor in the supercapacitor unit.

[0052] In the present application, the high-voltage box is used to achieve electrical connection between the supercapacitor unit and the power unit.

[0053] A switching power supply is provided in the high-voltage box. The power taking point of the switching power supply includes a first power taking point. The first power taking point is connected to the positive output terminal of the power unit.

[0054] exist Figure 1 In the figure, DCDC power supply refers to the switching power supply. DC1+ refers to the first power supply point.

[0055] When the supercapacitor is in a charging state, the switching power supply supplies power to the first capacitance management unit in the supercapacitor unit through the first power point.

[0056] In the present application, the supercapacitor unit is used to provide active power support for the static synchronous condenser.

[0057] The supercapacitor unit includes a supercapacitor and a first capacitance management unit. The supercapacitor is electrically connected to the first capacitance management unit. The first capacitance management unit draws power from the switching power supply. The first capacitance management unit is used to monitor the supercapacitor in the charging state and the supercapacitor in the operating state (i.e., the working state).

[0058] In the present application, the supercapacitor is in the form of a supercapacitor cluster, which is composed of multiple supercapacitor modules.

[0059] exist Figure 1 In the figure, supercapacitors are supercapacitors, which include supercapacitors 1 to n. Each supercapacitor corresponds to a capacitor management unit (CMU). In this application, the CMU in the supercapacitor unit is referred to as the first capacitor management unit. Figure 1 In the example, CMU1-CMUn are all first capacitance management units.

[0060] In the present application, when the voltage of the supercapacitor is lower than a preset threshold due to self-discharge and the supercapacitor needs to be charged, the switching power supply can draw power from the first power point to supply power to the first capacity management unit, so that the first capacity management unit remains in a working state. There will be no situation in the related art where the supercapacitor is in an unmonitored state for a period of time while charging the supercapacitor, and the safety hazards caused by this uncontrolled state can be avoided.

[0061] In addition, this application does not require the use of an isolation transformer to power the supercapacitor energy storage management system, has a simple structure and low cost, and does not require the use of a conventional low-voltage isolation power supply method, and has strong applicability.

[0062] In conjunction with the above embodiments, in one implementation, a second capacitance management unit is further provided within the high-voltage box, electrically connected to the first capacitance management unit. The second capacitance management unit is configured to monitor the supercapacitor in a charging and operating state and the first capacitance management unit in an operating state.

[0063] exist Figure 1 In the embodiment, CCU is a central control unit (Central Control Unit). In this application, the CCU in the high-voltage box is referred to as the second capacitance management unit.

[0064] In this application, the supercapacitor energy storage management system (Capacitor Management System, CMS) is divided into two levels: the first level is the CCU and the second level is the CMU. The CCU is placed in the high-voltage box and its power supply is taken from the DC-DC switching power supply. The CMU is installed on the supercapacitor module panel and its power supply is taken from the DC-DC switching power supply in the high-voltage box. This method ensures that the DC-DC switching power supply, CMU, and CCU are all at the same potential point. Because the high-voltage box and the supercapacitor energy storage management system frame are at the same potential, the supercapacitor energy storage management system is isolated from the ground by insulators, which can realize power supply under the high-voltage system without the need for introducing an isolated power supply.

[0065] In this application, since both the CCU and CMU draw power from the switching power supply, when the switching power supply is in working state, the CCU and CMU can directly enter the working state, thereby jointly supervising the charging process of the supercapacitor and ensuring the stable operation of the static synchronous phase condenser.

[0066] In combination with the above embodiments, in one embodiment, a supercapacitor charging circuit is also provided in the high-voltage box, and the supercapacitor charging circuit is electrically connected to the positive output terminal of the power unit and the positive input terminal of the switching power supply, respectively. The supercapacitor charging circuit is located after the first power supply point, and the power unit includes a DC bus capacitor.

[0067] The charging circuit of the supercapacitor is used to charge the supercapacitor when the voltage across the DC bus capacitor is greater than or equal to a first voltage threshold and the voltage across the supercapacitor is lower than a second voltage threshold.

[0068] like Figure 1 As shown, the charging circuit of the supercapacitor includes contactors KM1, KM2 and resistor R2. KM1 serves as a charging switch for the supercapacitor, KM2 serves as a charging bypass switch for the supercapacitor, and R2 serves as a charging resistor for the supercapacitor.

[0069] In the present application, when the voltage across the DC bus capacitor is greater than or equal to a first voltage threshold and the voltage across the supercapacitor is lower than a second voltage threshold, it can be determined that the supercapacitor needs to be charged.

[0070] When charging the supercapacitor, close KM1 and charge the supercapacitor through resistor R2. When stopping charging, close KM2.

[0071] In the present application, if the voltage across the supercapacitor is lower than the second voltage threshold, but the voltage across the DC bus capacitor is lower than the first voltage threshold, it is necessary to first charge the DC bus capacitor in the power unit through the charging circuit in the main circuit until the voltage across the DC bus capacitor in the power unit is greater than or equal to the first voltage threshold before charging the supercapacitor.

[0072] The second voltage threshold is usually a smaller value, such as a value close to 0. The first voltage threshold is usually a larger value, such as 250 V. The first voltage threshold and the second voltage threshold can be set based on experience, and this application does not impose any restrictions on this.

[0073] In the present application, the supercapacitor is charged only when the voltage across the DC bus capacitor of the power unit is greater than or equal to the first voltage threshold and the voltage across the supercapacitor is lower than the second voltage threshold, thereby ensuring smooth charging of the supercapacitor.

[0074] In combination with the above embodiments, in one embodiment, the power supply point of the switching power supply also includes a second power supply point, which is located after the charging circuit of the supercapacitor. A diode module is also provided in the high-voltage box, and the input end of the diode module is electrically connected to the output end of the charging circuit of the supercapacitor. The output end of the diode module is connected to the positive input end of the switching power supply, and the input end of the diode module is connected to the first power supply point and the second power supply point.

[0075] The diode module is used to control the switching power supply to obtain power from the first power point or the second power point.

[0076] exist Figure 1 In the figure, DC2+ indicates the second power supply point.

[0077] The diode module can select two separate diodes or use modular devices. This application does not impose any restrictions on this, as long as the diode module can control the switching power supply to draw power from the first power point or the second power point.

[0078] In one embodiment, the diode module includes a first diode and a second diode, the first diode and the second diode are connected to a common cathode, the cathode of the first diode or the second diode is connected to the positive input terminal of the switching power supply, the anode of the first diode is connected to the first power supply point, and the anode of the second diode is connected to the second power supply point.

[0079] The first diode is used to supply power to the switching power supply through the first power point.

[0080] The second diode is used to supply power to the switching power supply through the second power point.

[0081] like Figure 1 As shown, A2 is the anode of the lower diode in the diode module (hereafter referred to as the first diode). This is the forward end through which current flows into the diode and is connected to DC1+. K2 is the cathode of the first diode. This is the forward end through which current flows out of the diode and, when connected to K1, is connected to the positive terminal of the DC-DC power supply.

[0082] A1 is the anode of the top diode in the diode module (hereafter referred to as the second diode). This is the forward end of the diode, where current flows into, and is connected to DC2+. K1 is the cathode of the second diode, where current flows out of the forward end.

[0083] In this application, the A poles of the two diodes are respectively connected to the two positive points of the high-voltage box (ie DC1+ and DC2+).

[0084] like Figure 1 As shown, in the present application, the supercapacitor energy storage management system also includes a filtering unit, which is arranged between the power unit and the high-voltage box. The first power point is connected to the positive output end of the filtering unit. The filtering unit is used to filter out the voltage ripple and high-frequency noise in the DC output of the power unit.

[0085] Secondly, in Figure 1 In the figure, FU1 is a fuse used to provide overcurrent protection for the supercapacitor circuit. QF is a circuit breaker used to provide short circuit or overload protection.

[0086] In this application, the charging resistor of the supercapacitor (ie R2) is built into the high-voltage box, and the charging resistor of the supercapacitor is not designed on the main circuit of the device.

[0087] The relationship between the high voltage box, power unit and super capacitor is as follows Figure 2 shown. Figure 2 This is a schematic diagram of the principle of a high-voltage box shown in an embodiment of the present application.

[0088] In this application, the supercapacitor energy storage management system adopts a cascade mode and has built-in support capacitors (i.e. DC bus capacitors). The connection mode can be star connection or delta connection. Figure 3 As shown, the corner connection method is as follows Figure 4 shown. Figure 3 This is a schematic diagram of a stationary synchronous condenser using a star connection method according to an embodiment of the present application. Figure 4 This is a schematic diagram of a stationary synchronous condenser using a delta connection method according to an embodiment of the present application.

[0089] exist Figure 3 In the diagram, the top 35kV busbar and the equipment directly connected to it (such as circuit breaker QF2, voltage transformer TV1, etc.) represent the AC side, which is the interface between the entire static synchronous condenser and the external 35kV AC power system.

[0090] The main circuit refers to the main power path running through the entire static synchronous condenser from the AC side access point (starting from after the circuit breaker QF2 or the disconnector QS3).

[0091] exist Figure 3 In the diagram, QE2 and QE3 both represent earthing switches, QF2 represents a circuit breaker, TA1 represents a current transformer, QS3 represents a disconnect switch, (QC + R) represents the charging circuit in the main circuit (hereinafter referred to as the first charging circuit), QC represents the charging switch in the main circuit, R represents the charging resistor in the main circuit, and L represents the reactor in the main circuit. LA1-LA3 represent current transformers. AM1-AMn / BM1-BMn / CM1-CMn represent the series power cells in phases A, B, and C. AC1-ACn / BC1-BCn / CC1-CCn represent high-voltage boxes, and AD1-ADn / BD1-BDn / CD1-CDn represent supercapacitor energy storage units (supercapacitor clusters).

[0092] Similarly, in Figure 4In the figure, QF2 represents a circuit breaker, QE2 and QE3 both represent earthing switches, TA1 represents a current transformer, QS3 represents a disconnect switch, (QC + R) represents the charging circuit in the main circuit, QC represents the charging switch in the main circuit, and R represents the charging resistor in the main circuit. L represents the reactor in the main circuit. LA1-LA3 represent current transformers. AM1-AMn / BM1-BMn / CM1-CMn represent the series power cells in phases A, B, and C. AC1-ACn / BC1-BCn / CC1-CCn represent high-voltage boxes, and AD1-ADn / BD1-BDn / CD1-CDn represent supercapacitor energy storage units (supercapacitor clusters).

[0093] In this application, the AC side has a main circuit charging circuit, including a main circuit charging resistor (ie R) and a charging switch (ie QC). The charging circuit is used to charge the support capacitor in the super-capacitor energy storage management system. Therefore, when it is detected that the voltage across the DC bus capacitor is less than the first voltage threshold, the DC bus capacitor can be charged through the main circuit charging circuit. Specifically, Figure 3 For example, when the charging switch QC is disconnected, the DC bus capacitor can be charged through the charging resistor R, and when the charging switch QC is closed, the charging operation of the DC bus capacitor can be stopped.

[0094] In this application, the maximum input voltage that the DCDC power supply can withstand needs to be higher than the maximum rated operating voltage that may occur under normal or abnormal conditions on the DC bus to which it is connected (i.e., the line where DC1+ or DC2+ is located). Since the DCDC power supply draws power from DC1+ or DC2+, the voltage of the high-voltage DC line where DC1+ or DC2+ is located may fluctuate, and even reach a peak under certain operating conditions. In order to prevent the DCDC power supply from being damaged due to excessively high input voltage, it is necessary to select a model with a sufficiently high maximum input voltage tolerance to leave a safety margin. The minimum value of the input voltage of the DCDC power supply needs to be lower than the first voltage threshold corresponding to the support capacitor. In addition, the output voltage and power of the DCDC power supply must also meet the requirements of the CMU and CCU.

[0095] In one embodiment, the input voltage range of the DCDC power supply may theoretically be 250 V-1500 V, where 250 V is the first voltage threshold. In actual implementation, the minimum operating voltage of the DCDC power supply must be lower than 250 V to ensure reliable startup and design margin.

[0096] In this application, the power unit uses a full-bridge or half-bridge circuit topology, with DC bus capacitors configured on its DC side (or DC link). The module uses a metal housing that is fastened to the mounting frame with bolts (or screws) to ensure equipotential connection with the frame.

[0097] In this application, the high-voltage box adopts a metal casing, which is connected to the installation frame by bolts (or screws) to ensure equal potential. The CCU, contactor, sampling unit and other control units in the high-voltage box are all powered by a built-in switching power supply (i.e., DCDC power supply). The metal casing of the built-in switching power supply needs to be reliably connected to the box body of the high-voltage box through a wire to achieve equal potential (i.e., connected to the common reference potential of this unit). The input stage diode of the switching power supply and its module itself must be selected as a device that can meet the maximum DC voltage tolerance requirements inside the high-voltage box. Ultimately, the installation frame of the super-capacity energy storage management system, the casing of the power unit, the box body of the high-voltage box, and the metal casings or reference grounds of the main components installed inside it must all be reliably connected to each other to form a unified equipotential body.

[0098] In this application, the supercapacitor unit body is made of metal and connected to the mounting frame via bolts (or screws) to ensure equipotential connection. The CMU housing is also made of metal and is reliably connected to the installed supercapacitor unit structure via wires to achieve equipotential connection. Because the CMU's power supply terminals and signal acquisition ports process low-voltage signals within a floating potential, their mutual insulation only needs to meet the performance requirements of a conventional low-voltage system. Conventional low-voltage shielded cables should be used for the communication cables between the CMU and CCU. To improve power supply reliability, the CMU power supply network can be designed as a ring or two-end power supply structure (for example, power cables are connected to both the beginning and end of a CMU chain) to ensure redundant power supply. The CCU is equipped with at least two communication output interfaces to meet the requirements of flexible CMU chain connection. A high-voltage insulator is installed at the bottom of the overall mounting frame of the supercapacitor energy storage management system to provide high-voltage isolation of the entire unit from the ground (or mounting foundation).

[0099] In this application, Figure 3 or Figure 4 In the cascaded multilevel topology shown, multiple supercapacitor energy storage management systems are connected in series within each phase (arm). The entire series chain of supercapacitor energy storage management systems is connected to the high-voltage AC system via a main reactor. Each supercapacitor energy storage management system (including its internal power unit, high-voltage box, and supercapacitor unit) operates as a whole at a high potential relative to ground. To ensure safe operation, reliable high-voltage insulation measures (such as high-voltage insulators or sufficient insulation distance) must be implemented between adjacent supercapacitor energy storage management systems and between them and ground. This series structure ensures that the high-voltage system voltage is (approximately) evenly distributed to each supercapacitor energy storage management system in the chain, achieving voltage sharing.

[0100] In this application, the supercapacitor management system (CMS) employs a two-tier architecture: the bottom tier is the CMU, which directly manages the supercapacitor modules, and the upper tier is the CCU, which is responsible for reliable communication with and management of its subordinate CMUs. Since the entire supercapacitor energy storage management system operates at a high potential relative to ground, the CMS also operates at this floating potential. Both the CMU and CCU are powered directly from the switching power supply (DC-DC power supply) built into the high-voltage box, connected in parallel.

[0101] Therefore, implementing the solution proposed in this application, the energy storage management system (CMS) is divided into two stages. In the absence of an initial voltage on the supercapacitor, the CMS can indirectly obtain its operating power from the DC voltage (the voltage of the DC bus capacitor) already established within the supercapacitor energy storage management system. This effectively decouples the CMS power-up process from the supercapacitor charging process.

[0102] In this application, the output voltage of the switching power supply must meet the rated operating voltage requirements of the CMU and CCU.

[0103] (1) Capacity of switching power supply The choices are as follows:

[0104]

[0105] in, Indicates the capacity of the CMU at rated working conditions, in W; Indicates the capacity of the CCU at rated working conditions, in W; Indicates the sum of the rated capacities of the devices connected to the switching power supply in the high-voltage box. M indicates the number of connected CMUs; N indicates the number of connected CCUs; For the design margin, the installation space and power margin of the high-voltage box need to be considered. Generally, 1.2 is taken.

[0106] (2) The maximum input voltage of the switching power supply The values ​​are as follows:

[0107]

[0108] in, Indicates the maximum DC voltage of the high voltage box; Indicates the maximum DC voltage of the supercapacity energy storage management system; Indicates the maximum operating voltage of the supercapacitor; To design margin, the system operation reliability needs to be considered. Generally, 1.3 is taken.

[0109] (3) Minimum input voltage of the switching power supply The values ​​are as follows:

[0110]

[0111] in, To design margin, the system operation reliability needs to be considered. Generally, 0.8 is taken; Indicates the voltage of the support capacitor after charging is completed.

[0112] When the static synchronous condenser adopts star-connected topology, The design method is as follows:

[0113]

[0114] in, Indicates the system line voltage; Indicates the number of single-phase series connections in a star-connected topology.

[0115] When the static synchronous condenser adopts the delta topology, The design method is as follows:

[0116]

[0117] in, Indicates the system line voltage; Indicates the number of series connections for a single phase in delta topology.

[0118] (4) The specific selection of diodes is as follows:

[0119] The diode internal resistance deviation cannot exceed ;

[0120] Rated voltage ;

[0121] Rated current ;

[0122] is the rated current of the switching power supply.

[0123] Based on the above-mentioned supercapacitor energy storage management system in the static synchronous condenser, the supercapacitor charging method based on the supercapacitor energy storage management system will be described in detail below. The method of the present application is applied to the controller in the static synchronous condenser, and the controller is electrically connected to the power unit. Figure 5 This is a flow chart of an overcapacity charging method of an overcapacity energy storage management system in a static synchronous condenser according to an embodiment of the present application. Figure 5 The supercapacity charging method of the present application includes the following steps:

[0124] Step 101: When it is determined that the supercapacitor is to be charged, the switching power supply is controlled to enter an operating state through a first power supply point.

[0125] Before step 101 , the following steps need to be performed: when the voltage across the supercapacitor is lower than the second voltage threshold, determining whether the voltage across the DC bus capacitor is greater than or equal to the first voltage threshold.

[0126] In the present application, when the voltage across the DC bus capacitor is greater than or equal to the first voltage threshold, step 101 is executed again, that is, the switching power supply is controlled to enter the operating state through the first power supply point.

[0127] Since the first power supply point is connected to the positive output end of the filter unit, that is, the switching power supply can directly draw power from the first power supply point, if it is detected that the voltage across the DC bus capacitor is greater than or equal to the first voltage threshold, the switching power supply can be directly controlled to enter the operating state.

[0128] If the voltage across the DC bus capacitor is less than the first voltage threshold, the DC bus capacitor must first be charged through the charging circuit of the main circuit until the voltage across the DC bus capacitor is greater than or equal to the first voltage threshold.

[0129] Step 102: When the switching power supply is in an operating state, control the first capacitance management unit to enter an operating state.

[0130] In the present application, since the first capacitance management unit draws power from the switching power supply, when the switching power supply is in the running state, the first capacitance management unit can directly enter the running state.

[0131] Step 103: When the first capacitance management unit is in the operating state, control the supercapacitor to enter the charging state.

[0132] In this step, when it is determined that the first capacity management unit is in the operating state, the supercapacitor is charged, so that the first capacity management unit can monitor the entire charging process of the supercapacitor.

[0133] In the present application, when the supercapacitor needs to be charged, the switching power supply can draw power from the first power point to power the first capacity management unit, so that the first capacity management unit remains in operation. There is no situation in the related art where the supercapacitor is in an unmonitored state during the period of time when the supercapacitor is being charged, thus avoiding the safety hazards caused by this uncontrolled state. In addition, the present application does not require the use of an isolation transformer for the power supply of the supercapacitor energy storage management system, which has a simple structure, low cost, and no need to use a conventional low-voltage isolated power supply method, making it highly applicable.

[0134] In combination with the above embodiments, in one implementation, after controlling the switching power supply to enter the operating state, the method of the present application may further include:

[0135] When the switching power supply is in the operating state, the second capacitance management unit is controlled to enter the operating state.

[0136] Accordingly, when the first capacitance management unit is in the running state, controlling the supercapacitor to enter the charging state includes:

[0137] When the first capacitance management unit is in the running state, if the second capacitance management unit is in the running state, the supercapacitor is controlled to enter the charging state.

[0138] In this application, the supercapacitor energy storage management system CMS is divided into two levels, the first level is CCU and the second level is CMU. Since both CCU and CMU draw power from the switching power supply, when the switching power supply is in operation, CCU and CMU can directly enter the operation state, thereby jointly supervising the charging process of the supercapacitor and ensuring the stable operation of the static synchronous phase regulator.

[0139] In combination with the above embodiments, in one implementation, controlling the supercapacitor to enter a charging state includes:

[0140] The supercapacitor is controlled to enter a charging state through the supercapacitor charging circuit.

[0141] As before, when charging the supercapacitor, the contactor KM1 is closed to charge the supercapacitor through the charging resistor R2. When stopping the charging operation of the supercapacitor, the contactor KM2 is closed.

[0142] In combination with the above embodiments, in one implementation, after controlling the supercapacitor to enter a charging state, the method of the present application may further include:

[0143] The diode module is used to control the switching power supply to obtain power from the first power point or the second power point.

[0144] Specifically, the diode module includes a first diode and a second diode, the first diode and the second diode are connected to a common cathode, the positive input end of the switching power supply is connected to the cathode of the first diode or the second diode, the anode of the first diode is connected to the first power point, and the anode of the second diode is connected to the second power point.

[0145] Accordingly, controlling the switching power supply to draw power from the first power point, or drawing power from the second power point, specifically includes:

[0146] The switching power supply is controlled by the first diode to obtain power from the first power point, or the switching power supply is controlled by the second diode to obtain power from the second power point.

[0147] In this application, the supercapacitor energy storage management system CMS no longer directly depends on the voltage state of the supercapacitor itself. The DCDC power supply preferentially draws power from DC1+, ensuring that the startup of the CMS does not depend on whether the supercapacitor (DC2+) has power, thereby decoupling the charging process of the supercapacitor from the charging process of the supercapacitor energy storage management system.

[0148] In combination with the above embodiments, in one implementation, after controlling the supercapacitor to enter a charging state, the method of the present application may further include:

[0149] When the voltage difference between the voltage across the supercapacitor and the voltage across the DC bus capacitor is within a preset voltage difference range, the supercapacitor is controlled to exit the charging state.

[0150] Among them, the preset pressure difference range can be set according to actual needs.

[0151] Combine Figure 3 The structure in the figure is shown in FIG. 1 . The charging process of the supercapacitor is described below with a complete embodiment, which includes the following steps:

[0152] Step 1: Before starting, disconnect the switches of each circuit in the static synchronous condenser and keep the circuit breaker QF in the high-voltage box in the closed state;

[0153] Step 2: Before charging, obtain the voltage across the support capacitor (DC bus capacitor) in the power unit and determine whether the voltage is greater than or equal to a first voltage threshold (e.g., 250V). If not, proceed to step 3; if so, proceed to step 4.

[0154] Step 3: Determine whether the supercapacitor is normal. If it is normal, start the charging circuit of the main circuit to charge the support capacitor. When the voltage across the support capacitors in all supercapacitor energy storage management systems reaches the design value (e.g., 400V) (i.e., the voltage across the support capacitors reaches stability), close the charging bypass switch QC in the charging circuit of the main circuit (i.e., the current no longer flows through the resistor R), so that the voltage across the support capacitors is maintained at the design value (e.g., 400V). In other words, the DC voltage inside the supercapacitor energy storage management system is stabilized at the design value (e.g., 400V) working level.

[0155] Step 4: When the voltage across the supporting capacitor is greater than or equal to the first voltage threshold, the DC-DC power supply in the high-voltage box starts operating, and the CCU and CMU also start operating. At this time, the voltage across the supercapacitor is lower than the second voltage threshold. For example, the voltage across the supercapacitor is 0, and the second voltage threshold is a value slightly greater than 0.

[0156] Step 5: Close the charging switch KM1 in the supercapacitor charging circuit in the high-voltage box to charge the supercapacitor. At this time, since both the CCU and CMU are in operation, the supercapacitor charging process can be monitored in real time.

[0157] Step 6: When the voltage difference between the supercapacitor and the support capacitor is within the preset voltage difference range, close the charging bypass switch KM2 in the supercapacitor charging circuit. At this point, the charging of the supercapacitor is completed.

[0158] In subsequent steps, the SCMS uses the supercapacitor energy storage management system to further adjust the supercapacitor voltage to ensure it reaches the desired operating state. This means that the SCMS leverages the power electronics conversion capabilities of the power unit to proactively and precisely control the supercapacitor voltage, ensuring the entire energy storage system is fully operational for subsequent tasks such as phase modulation and active power support.

[0159] The solution of the present application not only solves the problem of being unable to monitor the charging process of the supercapacitor when the supercapacitor voltage is low, but also realizes the isolation of the primary and secondary voltages of the CMS in the high-voltage system, that is, reliable high-voltage electrical isolation is achieved between the monitoring circuit (primary) with a high-voltage floating potential and the external circuit (secondary) with a low voltage or ground potential, providing effective technical support for the application of high-voltage static synchronous condensers.

[0160] In summary, the implementation of the solution of the present application can enable the high-voltage static synchronous phase condenser equipment to monitor the charging status of the supercapacitor throughout the entire process when the supercapacitor is at zero voltage (or the voltage of the supercapacitor is lower than the second voltage threshold) when the whole machine is started. The method disclosed herein decouples the power supply of the supercapacitor energy storage management system (CMS) from the voltage state of the supercapacitor (i.e., it no longer directly depends on the voltage state of the supercapacitor itself. By designing the DC-DC power supply to preferentially draw power from DC1+, the startup of the CMS is ensured to be independent of whether the supercapacitor (DC2+) has power). Furthermore, the supercapacitor charging process is decoupled from the charging process of the supercapacitor energy storage management system (the charging process of the external supercapacitor is separated in time and circuit from the charging process of the support capacitor within the supercapacitor energy storage management system. The main circuit is charged first (for the support capacitor), and then the supercapacitor is charged after the CMS is started. This completely solves the problem of being unable to monitor the charging process after the supercapacitor voltage falls below the second voltage threshold. By arranging the DC-DC power supply within the high-voltage box (in the same floating potential reference system as the CCU / CMU), the present application avoids the need to add a complex, expensive, and bulky high-voltage isolation power supply module to power the CMS floating at a high potential, effectively resolving the problems in the related art.

[0161] The following describes the super-capacity charging device of the super-capacity energy storage management system in the static synchronous condenser provided by the present application. The super-capacity charging device of the static synchronous condenser described below and the super-capacity charging method of the static synchronous condenser described above can be referenced to each other. Figure 6 This is a structural block diagram of a super-capacitor charging device of a super-capacitor energy storage management system in a static synchronous condenser according to an embodiment of the present application. Figure 6 As shown, the supercapacitor charging device 600 of the present application includes:

[0162] A first control module 601 is configured to control the switching power supply to enter an operating state through the first power point when it is determined that the supercapacitor is to be charged;

[0163] A second control module 602 is configured to control the first capacitance management unit to enter an operating state when the switching power supply is in an operating state;

[0164] The third control module 603 is configured to control the supercapacitor to enter a charging state when the first capacitance management unit is in an operating state.

[0165] The supercapacitor charging device 600 provided in the present application further includes:

[0166] a fourth control module, configured to, after controlling the switching power supply to enter the running state, control the second capacitance management unit to enter the running state when the switching power supply is in the running state;

[0167] The third control module 603 includes:

[0168] The control submodule is configured to control the supercapacitor to enter a charging state when the first capacitance management unit is in an operating state and the second capacitance management unit is in an operating state.

[0169] The supercapacitor charging device 600 provided in the present application further includes:

[0170] A fifth control module is used to control the switching power supply to draw power from the first power point or the second power point through the diode module after controlling the supercapacitor to enter the charging state.

[0171] The supercapacitor charging device 600 provided in the present application further includes:

[0172] The sixth control module is used to control the supercapacitor to exit the charging state after controlling the supercapacitor to enter the charging state, when the voltage difference between the voltage across the supercapacitor and the voltage across the DC bus capacitor is within a preset voltage difference range.

[0173] Figure 7 FIG. 1 is a schematic diagram of the physical structure of an electronic device according to an embodiment of the present application. Figure 7 As shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communication bus 740, wherein the processor 710, the communications interface 720, and the memory 730 communicate with each other via the communication bus 740. The processor 710 may call logic instructions in the memory 730 to execute a supercapacitor charging method for a supercapacitor energy storage management system in a static synchronous condenser. The method includes: when it is determined that the supercapacitor is to be charged, controlling the switching power supply to enter an operating state through the first power point; when the switching power supply is in the operating state, controlling the first capacitance management unit to enter an operating state; and when the first capacitance management unit is in the operating state, controlling the supercapacitor to enter a charging state.

[0174] In addition, the logical instructions in the above-mentioned memory 730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application, or the part that contributes to the existing technology, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0175] On the other hand, the present application also provides a computer program product, which includes a computer program, which can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the supercapacitor charging method of the supercapacitor energy storage management system in a static synchronous phase regulator provided by the above methods. The method includes: when it is determined to charge the supercapacitor, through the first power point, controlling the switching power supply to enter an operating state; when the switching power supply is in an operating state, controlling the first capacitor management unit to enter an operating state; when the first capacitor management unit is in an operating state, controlling the supercapacitor to enter a charging state.

[0176] On the other hand, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute a supercapacitor charging method of a supercapacitor energy storage management system in a static synchronous condenser provided by the above methods. The method includes: when it is determined that the supercapacitor is to be charged, through the first power point, controlling the switching power supply to enter an operating state; when the switching power supply is in an operating state, controlling the first capacitor management unit to enter an operating state; when the first capacitor management unit is in an operating state, controlling the supercapacitor to enter a charging state.

[0177] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0178] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A supercapacitor energy storage management system in a static synchronous condenser, characterized in that: comprising a power unit, a high voltage box and a supercapacitor unit electrically connected in sequence; The power unit is used to realize power conversion during the charging and discharging process of the supercapacitor in the supercapacitor unit; The high-voltage box is used to realize the electrical connection between the supercapacitor unit and the power unit. A switching power supply is provided in the high-voltage box. The power supply point of the switching power supply includes a first power supply point. The first power supply point is connected to the positive output terminal of the power unit. When the supercapacitor is in the charging state, the switching power supply supplies power to the first capacitance management unit in the supercapacitor unit through the first power supply point. The supercapacitor unit is used to provide active power support for the static synchronous condenser. The supercapacitor unit includes a supercapacitor and a first capacitance management unit. The supercapacitor is electrically connected to the first capacitance management unit. The first capacitance management unit draws power from the switching power supply. The first capacitance management unit is used to monitor the supercapacitor in a charging and operating state. The high-voltage box is also provided with a supercapacitor charging circuit, which is electrically connected to the positive output terminal of the power unit and the positive input terminal of the switching power supply respectively. The supercapacitor charging circuit is located after the first power point, and the power unit includes a DC bus capacitor; The charging circuit of the supercapacitor is used to charge the supercapacitor when the voltage across the DC bus capacitor is greater than or equal to a first voltage threshold and the voltage across the supercapacitor is lower than a second voltage threshold.

2. The super-capacity energy storage management system in a static synchronous condenser according to claim 1, characterized in that: A second capacitance management unit is further provided in the high-voltage box, and the second capacitance management unit is electrically connected to the first capacitance management unit; The second capacitance management unit is used to monitor the supercapacitor in the charging and operating state and the first capacitance management unit in the operating state.

3. The super-capacity energy storage management system in a static synchronous condenser according to claim 1, characterized in that: The power supply point of the switching power supply also includes a second power supply point, which is located after the charging circuit of the supercapacitor. A diode module is further provided in the high-voltage box, and the input end of the diode module is electrically connected to the output end of the charging circuit of the supercapacitor, the output end of the diode module is connected to the positive input end of the switching power supply, and the input end of the diode module is connected to the first power supply point and the second power supply point; The diode module is used to control the switching power supply to obtain power from the first power point, or to obtain power from the second power point.

4. The super-capacity energy storage management system in a static synchronous condenser according to claim 3, characterized in that: The diode module includes a first diode and a second diode, the first diode and the second diode are connected to a common cathode, the cathode of the first diode or the second diode is connected to the positive input terminal of the switching power supply, the anode of the first diode is connected to the first power point, and the anode of the second diode is connected to the second power point; The first diode is used to supply power to the switching power supply through the first power point; The second diode is used to supply power to the switching power supply through the second power supply point.

5. A supercapacitor charging method for a supercapacitor energy storage management system in a static synchronous condenser according to any one of claims 1 to 4, characterized in that: A controller applied to the static synchronous condenser, the controller being electrically connected to the power unit, and the supercapacitor charging method comprising: When it is determined that the supercapacitor is to be charged, controlling the switching power supply to enter an operating state through the first power point; When the switching power supply is in an operating state, controlling the first capacitance management unit to enter an operating state; When the first capacitance management unit is in an operating state, the supercapacitor is controlled to enter a charging state.

6. The supercapacitor charging method according to claim 5, characterized in that: A second capacitance management unit is further provided in the high-voltage box. After controlling the switching power supply to enter the operating state, the method further includes: When the switching power supply is in an operating state, controlling the second capacitance management unit to enter an operating state; When the first capacitance management unit is in the running state, controlling the supercapacitor to enter the charging state includes: When the first capacitance management unit is in an operating state, if the second capacitance management unit is in an operating state, the supercapacitor is controlled to enter a charging state.

7. The supercapacitor charging method according to claim 5, characterized in that: The power supply point of the switching power supply further includes a second power supply point, and a diode module is further provided in the high-voltage box. After controlling the supercapacitor to enter a charging state, the method further includes: The diode module is used to control the switching power supply to obtain power from the first power point or the second power point.

8. The supercapacitor charging method according to claim 5, characterized in that: The power unit includes a DC bus capacitor. After controlling the supercapacitor to enter a charging state, the method further includes: When the voltage difference between the voltage across the supercapacitor and the voltage across the DC bus capacitor is within a preset voltage difference range, the supercapacitor is controlled to exit the charging state.

9. A supercapacitor charging device based on the supercapacitor charging method of the supercapacitor energy storage management system in a static synchronous condenser according to claim 5, characterized in that: include: a first control module, configured to control the switching power supply to enter an operating state through the first power point when it is determined that the supercapacitor is to be charged; a second control module, configured to control the first capacitance management unit to enter an operating state when the switching power supply is in an operating state; The third control module is used to control the supercapacitor to enter a charging state when the first capacitance management unit is in an operating state.

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