GOOSE (Generic Object Oriented Substation Event) and differential protection-based energy storage unit area protection control system and method

Abstract

The invention discloses an energy storage unit area protection control system and method based on GOOSE communication and differential protection, and aims at different faults of an AC side bus fault, a line fault, a transformer fault, a PCS AC side and the like of an energy storage unit. Multi-section stepped protection of the alternating current side of the energy storage unit is formed by configuring busbar differential protection, unit differential protection, longitudinal differential protection, quick-break overcurrent, frequency, voltage and temperature protection, SV sampling, GOOSE tripping and communication locking are adopted between the protection device and a PCS inverter, and quick removal, timely isolation and shutdown during various inter-phase short circuits, overload faults and PCS body faults are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage system protection control, and more specifically, relates to an energy storage unit regional protection control system based on GOOSE communication and differential protection. Background Art

[0002] In recent years, my country's energy storage technology has developed rapidly, and more and more large-scale energy storage battery systems have been applied to power systems. However, due to the influence of power electronic devices, the short-circuit current is greatly reduced when a fault occurs, the system protection setting cannot meet the protection action requirements, and the reliability of relay protection is insufficient; there is a lack of effective coordination between the various levels of protection of the energy storage unit, the protection sensitivity is low, and it is easy to lose selectivity, expand the scope of the fault, and cause equipment damage. Summary of the invention

[0003] In order to solve the deficiencies in the prior art, the present invention provides a regional protection control system and method for energy storage units based on GOOSE communication and differential protection, which reasonably configures protection for different fault types, and configures current, voltage, frequency protection, temperature and other protections according to functional zoning to ensure timely and effective removal of various short-circuit faults.

[0004] The present invention adopts the following technical solutions. The first aspect of the present invention provides an energy storage unit regional protection control system based on GOOSE communication and differential protection, wherein the energy storage unit includes: including PCS and battery clusters, connected to the low-voltage bus, the low-voltage bus is connected to the medium-voltage branch bus through a step-up transformer and a high-voltage side switch of the step-up transformer, and the medium-voltage branch bus is connected to the medium-voltage bus as a medium-voltage bus incoming line through an incoming line switch, characterized in that the energy storage unit includes:

[0005] System protection zone, boost protection zone and PCS AC protection zone; the protection range of the system protection zone includes: medium voltage busbar, medium voltage incoming line and high voltage side of boost transformer; the protection range of the boost protection zone includes: high voltage side of boost transformer, low voltage side of boost transformer, auxiliary transformer and PCS AC side; the protection range of the PCS AC protection zone includes: PCS AC side and PCS power module; both the system protection zone and boost protection zone are equipped with differential protection devices;

[0006] The EMS monitoring system includes: a station control layer and a local control layer; the local control layer adopts optical fiber Ethernet, GOOSE and SV common network, and the protection devices and control devices of the system protection zone, boost protection zone and PCS AC protection zone are connected to the station control layer and the local control layer.

[0007] Preferably, the protection devices configured in the system protection zone include: a medium voltage bus protection device, a unit differential protection device and an island protection device; the unit differential protection device, the island protection device and the PCS inverter use GOOSE communication to access the control layer network;

[0008] The protection function of the medium-voltage busbar protection device is configured as bus differential protection; the protection function of the unit differential protection device is configured as energy storage unit differential protection and medium-voltage busbar incoming line quick-break overcurrent protection; the protection function of the island protection device is configured as island protection.

[0009] Preferably, the protection devices configured in the boost protection zone include: a boost transformer longitudinal differential protection device and an auxiliary transformer high voltage fuse; the boost transformer longitudinal differential protection device and the PCS inverter use GOOSE communication to access the control layer network;

[0010] The protection function of the boost transformer longitudinal differential protection device is configured as longitudinal differential protection, boost transformer high-voltage side quick-break overcurrent protection and boost transformer non-electrical quantity protection; the protection function of the auxiliary transformer high-voltage fuse is configured as auxiliary transformer overcurrent protection.

[0011] Preferably, the protection devices configured in the PCS AC protection zone include: a PCS inverter current protection device, a PCS inverter voltage protection device, a PCS inverter frequency protection device, a PCS inverter island protection device, a power module drive protection device and a power module temperature protection device;

[0012] The protection functions of the PCS inverter current protection device are configured as PCS inverter quick-break, overcurrent and insulation protection;

[0013] The protection functions of the PCS inverter voltage protection device are configured as overvoltage, low voltage, negative sequence voltage protection and synchronization;

[0014] The protection functions of the PCS inverter frequency protection device are configured as over-frequency, under-frequency protection and synchronization;

[0015] The protection function of the PCS inverter island protection device is configured as frequency and voltage protection;

[0016] The protection functions of the AC circuit breaker protection device are configured as PCS AC side quick-break overcurrent protection, short circuit instantaneous, short circuit short delay and overload protection;

[0017] The protection function of the power module drive protection device is configured as IGBT drive protection;

[0018] The protection function of the power module temperature protection device is configured as power module temperature protection.

[0019] A second aspect of the present invention provides a method for controlling regional protection of energy storage units based on GOOSE communication and differential protection, which is run on the regional protection control system of energy storage units based on GOOSE communication and differential protection;

[0020] In the system protection zone, if the fault point is located on the medium-voltage bus, the bus differential protection is configured as the main protection, and the overcurrent protection on the medium-voltage side of the main transformer on the system side is the backup protection; if the fault point is located on the medium-voltage incoming line, the energy storage unit differential protection is configured as the main protection, and the medium-voltage bus incoming line quick-break overcurrent protection is configured as the backup protection;

[0021] In the boost protection zone, if the fault point is located on the high-voltage side or low-voltage side of the boost transformer, the boost transformer longitudinal differential protection is configured as the main protection, and the high-voltage side quick-break overcurrent protection of the boost transformer is the backup protection; if the fault point is located on the auxiliary transformer, the auxiliary transformer high-voltage side fuse is the main protection, and the high-voltage side quick-break overcurrent protection of the boost transformer is the backup protection;

[0022] In the PCS AC protection zone, for the fault point located on the PCS AC side, IGBT drive protection, PCS AC quick-break protection, and AC circuit breaker short-circuit instantaneous protection are configured as main protection, and PCS AC overcurrent protection and AC circuit breaker overcurrent protection are configured as backup protection.

[0023] Preferably, if the fault point is located on the medium-voltage bus, the bus protection is activated during the fault and all the circuit breakers of the medium-voltage bus are switched; the overcurrent protection on the medium-voltage side of the main transformer on the system side is activated after a delay and the circuit breaker on the low-voltage side of the main transformer is tripped; the island protection of the island protection device is activated, and the island protection device and the PCS inverter communicate via the control layer network using GOOSE, and the PCS inverter pulse is quickly locked when the island protection is activated; or the PCS island protection of the PCS inverter island protection device is delayed and the PCS is shut down.

[0024] Preferably, when the fault point is located on the medium voltage incoming line, the protection action trips the switch between the medium voltage bus and the medium voltage incoming line, and the switch between the high voltage side of the step-up transformer and the medium voltage incoming line; the unit differential protection device and the PCS inverter communicate via the control layer network using GOOSE, and the PCS inverter pulse is quickly locked when the energy storage unit differential protection is actuated;

[0025] The PCS inverter voltage protection and PCS inverter island protection are backup protections, blocking pulses and tripping the AC circuit breaker on the PCS AC side.

[0026] Preferably, if the fault point is located on the high-voltage side of the boost transformer or the low-voltage side of the boost transformer, the protection action trips the high-voltage side switch of the boost transformer when a fault occurs, and the boost transformer longitudinal differential protection device communicates with the PCS inverter via the control layer network using GOOSE. When the boost transformer longitudinal differential protection is performed, the PCS inverter pulse is quickly locked and the AC circuit breaker is tripped;

[0027] PCS inverter voltage protection and PCS inverter island protection are backup protections. If the main protection does not work in case of a fault, the pulse will be locked and the AC circuit breaker on the PCS AC side will be tripped. In addition, GOOSE is used to communicate with the boost transformer longitudinal differential protection device through the control layer network to jointly trip the boost transformer side switch.

[0028] Preferably, if the fault point is located at the auxiliary transformer, the fuse on the high-voltage side of the auxiliary transformer is the main protection, and the auxiliary transformer fuse will trip when a fault occurs; the quick-break overcurrent protection on the high-voltage side of the boost transformer is the backup protection, and the switch on the high-voltage side of the boost transformer will trip when a fault occurs.

[0029] Preferably, if the fault point is located on the AC side of the PCS, the protection action blocks the pulse and trips the AC circuit breaker when the fault occurs. The PCS communicates with the BMS and notifies the BMS to power off the DC battery cluster.

[0030] The PCS module temperature is a backup protection. When the module temperature is higher than the set value, the pulse will trip the AC circuit breaker.

[0031] The PCS frequency and voltage are backup protection. When the frequency and voltage exceed the set value, the pulse will be locked to trip the AC circuit breaker.

[0032] Compared with the prior art, the beneficial effects of the present invention include at least: an energy storage unit regional protection control system based on GOOSE communication and differential principles, by configuring bus differential protection, unit differential protection, longitudinal differential protection, quick-break overcurrent protection, voltage, frequency protection, IGBT drive protection, power module protection, etc., the protection and control devices are connected to the local control layer, and GOOSE and SV are used in the same network to realize interlocking control functions such as fast sampling, tripping, and locking pulses, to ensure rapid fault removal, timely isolation and shutdown in case of bus faults, phase-to-phase short circuits, and overload faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Provide a wiring diagram for the energy storage unit system;

[0034] Figure 2 This is the EMS monitoring system diagram for the energy storage unit;

[0035] Figure 3 This is the energy storage unit protection configuration diagram. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0037] like Figures 1 to 3As shown, embodiment 1 of the present invention provides a regional protection control system for energy storage units based on GOOSE communication and differential protection, including: reasonably configuring protection for different fault types, and dividing into system protection zone, boost protection zone and PCS AC protection zone according to function. Mother differential protection, unit differential protection, longitudinal differential protection, quick-break overcurrent protection, voltage, frequency protection, IGBT drive protection, power module protection, etc. are configured in each protection zone to realize the functions of main protection, backup protection and auxiliary protection. The protection ranges between the system protection zone, boost protection zone and PCS AC protection zone are crossed, and the protection settings are coordinated, without protection dead zone.

[0038] Specifically, for different faults such as bus faults on the AC side of the energy storage unit, line faults, transformer faults, and PCS AC side faults, a multi-stage stepped protection for the AC side of the energy storage unit is formed by configuring bus differential protection, unit differential protection, longitudinal differential protection, quick-break overcurrent, frequency, voltage, and temperature protection combinations. SV sampling, GOOSE tripping, and communication interlocking are used between the protection device and the PCS inverter to achieve rapid removal, timely isolation, and shutdown of various phase-to-phase short circuits, overload faults, and PCS body faults.

[0039] The energy storage unit is connected to the low-voltage busbar, which is connected to the medium-voltage branch busbar via the step-up transformer and the high-voltage side switch of the step-up transformer. The medium-voltage branch busbar is connected to the medium-voltage busbar via the incoming switch as the medium-voltage busbar incoming line. The main transformer on the system side is the main transformer of the step-up station, and the low-voltage side of the main transformer on the system side is connected to the medium-voltage busbar.

[0040] The energy storage unit includes: PCS (Power Conversion System, energy storage converter) and battery cluster. The AC side of PCS is connected to the low-voltage bus, and the DC side is connected to the battery cluster. More specifically, PCS includes: AC circuit breaker and inverter as PCS power module. The AC side of inverter is connected to the low-voltage bus via AC circuit breaker, and the DC side of inverter is connected to the battery cluster. The low-voltage bus is also connected to an auxiliary transformer.

[0041] It is understandable that the energy storage system can be composed of multiple energy storage units, each energy storage unit can include multiple PCSs, and the DC side of the PCS can be composed of multiple battery clusters in parallel. For example, but not limited to, the low-voltage side of the system-side main transformer is connected to the 35kV bus of the energy storage system.

[0042] like Figure 2As shown in the figure, the EMS system (Energy Management System) adopts a hierarchical distributed design, including: station control layer and local control layer. The station control layer adopts 100M electrical Ethernet, and the local control layer adopts optical fiber Ethernet, GOOSE and SV common network. The protection device and control device are connected to the station control layer and the local control layer to realize interlocking control functions such as fast sampling, tripping, and blocking pulse.

[0043] Preferably, but not restrictively, the protection device, the control device and the station control layer of the EMS monitoring system communicate using an Ethernet port and the IEC-61850 protocol. The protection device and the PCS inverter are connected to the local control layer using the GOOSE protocol, and the transmission realizes interlocking control functions such as fast sampling, tripping, and blocking pulses, ensuring fast fault removal, timely isolation and shutdown in the event of bus faults, phase-to-phase short circuits, and overload faults.

[0044] The protection scope of the system protection zone includes: medium voltage busbar, medium voltage incoming line, and high voltage side of step-up transformer.

[0045] like Figure 2 As shown, the protection devices configured in the system protection zone include: medium voltage bus protection device, unit differential protection device and island protection device. The unit differential protection device, island protection device and PCS inverter use GOOSE communication to access the control layer network.

[0046] The protection function of the medium-voltage busbar protection device is configured as bus differential protection; the protection function of the unit differential protection device is configured as energy storage unit differential protection and medium-voltage busbar incoming line quick-break overcurrent protection; the protection function of the island protection device is configured as island protection.

[0047] Within the system protection zone, the fault point may be located at the medium voltage busbar or the medium voltage incoming line.

[0048] ① When the fault point is located on the medium-voltage bus, the bus differential protection is the main protection, and the overcurrent protection on the medium-voltage side of the main transformer on the system side is the backup protection.

[0049] When a fault occurs, the busbar protection is activated and all circuit breakers of the medium-voltage busbar are switched; the overcurrent protection on the medium-voltage side of the main transformer on the system side is activated after a delay, and the circuit breaker on the low-voltage side of the main transformer is tripped; the island protection of the island protection device is activated, and the island protection device and the PCS inverter use GOOSE communication through the control layer network. When the island protection is activated, the PCS inverter pulse is quickly locked; or the PCS island protection of the PCS inverter island protection device is delayed and the PCS is shut down.

[0050] ② When the fault point is located on the medium-voltage incoming line, the energy storage unit differential protection is the main protection, and the medium-voltage bus incoming line quick-break overcurrent protection is the backup protection.

[0051] In case of fault, the protection action trips the switch between the medium voltage busbar and the medium voltage incoming line, and the switch between the high voltage side of the step-up transformer and the medium voltage incoming line;

[0052] The unit differential protection device communicates with the PCS inverter via the control layer network using GOOSE. When the energy storage unit differential protection is activated, the PCS inverter pulse is quickly blocked.

[0053] Furthermore, the PCS inverter voltage protection and the PCS inverter island protection are backup protections, blocking pulses and tripping the AC circuit breaker on the PCS AC side.

[0054] The protection range of the boost protection zone includes: the high voltage side of the boost transformer, the low voltage side of the boost transformer, the auxiliary transformer and the AC side of the PCS.

[0055] The protection devices configured in the boost protection zone include: boost transformer longitudinal differential protection device and auxiliary transformer high voltage fuse. The boost transformer longitudinal differential protection device and PCS inverter use GOOSE communication to access the control layer network.

[0056] The protection function of the boost transformer longitudinal differential protection device is configured as longitudinal differential protection, boost transformer high-voltage side quick-break overcurrent protection and boost transformer non-electrical quantity protection; the protection function of the auxiliary transformer high-voltage fuse is configured as auxiliary transformer overcurrent protection.

[0057] In the boost protection zone, the fault point may be located at the high voltage side of the boost transformer, the low voltage side of the boost transformer or the auxiliary transformer.

[0058] ① If the fault point is located on the high-voltage side or the low-voltage side of the boost transformer, the boost transformer longitudinal differential protection is the main protection, and the high-voltage side quick-break overcurrent protection of the boost transformer is the backup protection;

[0059] When a fault occurs, the protection action trips the high-voltage side switch of the boost transformer. The boost transformer longitudinal differential protection device communicates with the PCS inverter via the control layer network using GOOSE. When the boost transformer longitudinal differential protection is in effect, the PCS inverter pulse is quickly locked and the AC circuit breaker is tripped.

[0060] PCS inverter voltage protection and PCS inverter island protection are backup protections. If the main protection does not work in case of a fault, the pulse will be locked and the AC circuit breaker on the PCS AC side will be tripped. In addition, GOOSE communication is adopted with the boost transformer longitudinal differential protection device through the control layer network to jointly trip the boost transformer high-voltage side switch.

[0061] ② If the fault point is located at the auxiliary transformer, the fuse on the high-voltage side of the auxiliary transformer is the main protection, and the auxiliary transformer fuse will trip in case of a fault; the quick-break overcurrent protection on the high-voltage side of the boost transformer is the backup protection, and the switch on the high-voltage side of the boost transformer will trip in case of a fault.

[0062] The protection scope of the PCS AC protection zone includes: PCS AC side and PCS power module.

[0063] The protection devices configured in the PCS AC protection zone include: PCS inverter current protection device, PCS inverter voltage protection device, PCS inverter frequency protection device, PCS inverter island protection device, power module drive protection device and power module temperature protection device.

[0064] The protection function of the PCS inverter current protection device is configured as PCS inverter quick-break, overcurrent and insulation protection; the protection function of the PCS inverter voltage protection device is configured as overvoltage, low voltage, negative sequence voltage protection and synchronization; the protection function of the PCS inverter frequency protection device is configured as overfrequency, low frequency protection and synchronization; the protection function of the PCS inverter island protection device is configured as frequency and voltage protection; the protection function of the AC circuit breaker protection device is configured as PCS AC side quick-break overcurrent protection, AC circuit breaker short circuit instantaneous protection, short circuit short delay and overload protection; the protection function of the power module drive protection device is configured as IGBT drive protection; the protection function of the power module temperature protection device is configured as power module temperature protection.

[0065] In the PCS AC protection zone, the fault point may be located at the AC side of the PCS inverter.

[0066] Configure PCS AC side quick-break overcurrent protection (ACK AC circuit breaker), PCS inverter quick-break overcurrent protection, PCS inverter voltage and frequency protection, IGBT drive protection, and power module temperature protection.

[0067] In case the fault point is located on the PCS AC side, IGBT drive protection, PCS AC quick-break protection, and AC circuit breaker short-circuit instantaneous protection are configured as the main protection, and PCS AC overcurrent protection and AC circuit breaker overcurrent protection are configured as backup protection. When a fault occurs, the protection action will lock the pulse and trip the AC circuit breaker. The PCS and BMS will communicate to notify the BMS to power off the DC battery cluster. The PCS module temperature is the backup protection. When the module temperature is higher than the set value, the locking pulse will trip the AC circuit breaker. The PCS frequency and voltage are the backup protection. When the frequency and voltage exceed the set value, the locking pulse will trip the AC circuit breaker.

[0068] The protection ranges of the system protection zone, boost protection zone, and PCS AC protection zone are intersected, and the protection settings are coordinated, with no protection dead zone. Figure 3 shown.

[0069] Embodiment 2 of the present invention provides a method for regional protection control of an energy storage unit based on GOOSE and differential protection, comprising the following steps:

[0070] Within the system protection zone, if the fault point is located on the medium-voltage bus, the bus differential protection is configured as the main protection, and the overcurrent protection on the medium-voltage side of the main transformer on the system side is configured as the backup protection; if the fault point is located on the medium-voltage incoming line, the energy storage unit differential protection is configured as the main protection, and the medium-voltage bus incoming line quick-break overcurrent protection is configured as the backup protection.

[0071] Specifically, if the fault point is located on the medium-voltage bus, the bus protection will be activated during the fault, and all the circuit breakers of the medium-voltage bus will be switched; the overcurrent protection on the medium-voltage side of the main transformer on the system side will be activated after a delay, and the circuit breaker on the low-voltage side of the main transformer will be tripped; the island protection of the island protection device will be activated, and the island protection device and the PCS inverter will communicate via the control layer network using GOOSE, and the PCS inverter pulse will be quickly locked when the island protection is activated; or the PCS island protection of the PCS inverter island protection device will cause the PCS to shut down after a delay.

[0072] When the fault point is located on the medium voltage incoming line, the protection action trips the switch between the medium voltage busbar and the medium voltage incoming line, and the switch between the high voltage side of the step-up transformer and the medium voltage incoming line; the unit differential protection device and the PCS inverter communicate via the control layer network using GOOSE, and the PCS inverter pulse is quickly blocked when the energy storage unit differential protection is actuated;

[0073] The PCS inverter voltage protection and PCS inverter island protection are backup protections, blocking pulses and tripping the AC circuit breaker on the PCS AC side.

[0074] In the boost protection zone, if the fault point is located on the high-voltage side or the low-voltage side of the boost transformer, the boost transformer longitudinal differential protection is configured as the main protection, and the boost transformer high-voltage side quick-break overcurrent protection is configured as the backup protection; if the fault point is located in the auxiliary transformer, the auxiliary transformer high-voltage side fuse is the main protection, and the boost transformer high-voltage side quick-break overcurrent protection is configured as the backup protection.

[0075] Specifically, if the fault point is located on the high-voltage side or the low-voltage side of the boost transformer, the protection action will trip the switch on the high-voltage side of the boost transformer when a fault occurs. The boost transformer longitudinal differential protection device communicates with the PCS inverter via the control layer network using GOOSE. When the boost transformer longitudinal differential protection occurs, the PCS inverter pulse is quickly locked and the AC circuit breaker is tripped. The PCS inverter voltage protection and the PCS inverter island protection are backup protections. If the main protection does not operate in the event of a fault, the pulse will be locked and the AC circuit breaker on the PCS AC side will be tripped. In addition, the boost transformer longitudinal differential protection device communicates with the PCS inverter via the control layer network using GOOSE to jointly trip the boost transformer side switch.

[0076] When the fault point is located at the auxiliary transformer, the fuse on the high-voltage side of the auxiliary transformer is the main protection, and the auxiliary transformer fuse will trip when a fault occurs; the quick-break overcurrent protection on the high-voltage side of the boost transformer is the backup protection, and the high-voltage side switch of the boost transformer will trip when a fault occurs.

[0077] In the PCS AC protection zone, for the fault point located on the PCS AC side, IGBT drive protection, PCS AC quick-break protection, and AC circuit breaker short-circuit instantaneous protection are configured as main protection, and PCS AC overcurrent protection and AC circuit breaker overcurrent protection are configured as backup protection.

[0078] Specifically, if the fault point is located on the PCS AC side, the protection action will lock the pulse and trip the AC circuit breaker when a fault occurs. The PCS and BMS will communicate to notify the BMS to power off the DC battery cluster. The PCS module temperature is a backup protection. When the module temperature is higher than the set value, the lock pulse will trip the AC circuit breaker. The PCS frequency and voltage are backup protection. When the frequency and voltage exceed the set value, the lock pulse will trip the AC circuit breaker.

[0079] In order to more clearly introduce the outstanding essential features of the present invention and the significant progress it brings to the prior art, an application example of implementing the present invention is introduced below.

[0080] In an exemplary but non-limiting embodiment, Figure 1 As shown, the 2.5MW / 10MWh energy storage system includes two 2.5MW energy storage units, namely, 1# energy storage unit and 2# energy storage unit; 1# energy storage unit and 2# energy storage unit are respectively connected to 35kV I branch bus and II branch bus through step-up transformers. 35kV I branch bus and II branch bus serve as 35kV incoming lines, which are connected to the 35kV bus through incoming line switches. The step-up transformer capacity is 2.5MVA.

[0081] Both the 1# and 2# energy storage units include two 1250kW DC / AC PCSs. The PCS AC side is connected to a 690V low-voltage busbar, and the PCS DC side consists of four battery clusters connected in parallel, with a DC side voltage of 1500V. The low-voltage busbar is also connected to an auxiliary transformer.

[0082] More specifically, the 1# energy storage unit includes: the first PCS and the second PCS; the first PCS includes: the AC circuit breaker ACK1 and the first inverter, the DC side of the first inverter is connected to the first battery cluster, and the AC side is connected to the 690V bus through the AC circuit breaker ACK1; the second PCS includes: the AC circuit breaker ACK2 and the second inverter, the DC side of the second inverter is connected to the second battery cluster, and the AC side is connected to the 690V bus through the AC circuit breaker ACK2. The main transformer on the system side is the main transformer of the booster station, and the low-voltage side of the main transformer on the system side is connected to the 35kV bus of the energy storage system.

[0083] In an exemplary but non-limiting embodiment, Figure 3 As shown, the protection range of the system protection zone includes 35kV busbar, 35kV incoming line, and 35kV step-up transformer high-voltage side, and is equipped with 35kV bus differential protection, unit differential protection, 35kV incoming line quick-break overcurrent protection and island protection.

[0084] ① For the 35kV bus fault point K25, the bus differential protection is the main protection, and the system side main transformer backup protection is the backup protection. When a fault occurs, the bus protection is activated and all bus circuit breakers are switched; the system side main transformer 35kV side overcurrent protection is activated after a delay, and the main transformer low-voltage side circuit breaker is tripped; the independent island protection is activated or the PCS island protection is delayed and the PCS is shut down.

[0085] ② For the fault at point K24 at the end of the 35kV line, the energy storage unit differential protection is the main protection, and the 35kV line quick-break overcurrent is the backup protection. When a fault occurs, the protection action trips the 35kV line 1DL switch and the 2DL and 3DL switches on the high-voltage side of the step-up transformer; the unit differential protection and PCS inverter are connected to the control layer network, using GOOSE communication. When the unit differential protection is actuated, the PCS inverter pulse is quickly blocked; the PCS inverter low-voltage protection and island protection are backup protection, blocking the pulse and tripping the PCS AC side ACK1 or ACK2 circuit breaker.

[0086] The protection range of the boost protection zone includes the high voltage side of the 35kV boost transformer, the low voltage side of the 35kV boost transformer, the auxiliary transformer, and the PCS AC side. It is equipped with longitudinal differential protection, 35kV boost transformer high voltage side quick-break overcurrent protection, boost transformer non-electrical quantity protection, and auxiliary transformer overcurrent protection.

[0087] For the faults at K23 on the high-voltage side and K22 on the low-voltage side of the boost transformer, the boost transformer differential protection is the main protection, and the quick-break overcurrent protection on the high-voltage side of the boost transformer is the backup protection. In case of fault, the protection will trip the 2DL switch (or 3DL) on the high-voltage side of the boost transformer. The boost transformer longitudinal differential protection and the PCS inverter are connected to the control layer network, and GOOSE communication is adopted. When the differential protection is actuated, the PCS inverter pulse is quickly locked, and the PCS AC circuit breakers ACK1 and ACK2 are tripped; the low-voltage protection and island protection of the PCS inverter are the backup protection. In case of fault, if the main protection does not actuate, the backup protection will actuate to lock the pulse and trip the ACK1 or ACK2 circuit breaker on the PCS AC side, and communicate with the boost differential protection GOOSE to jointly trip the 2DL (or 3DL) on the high-voltage side of the boost transformer.

[0088] ② For the fault of auxiliary transformer K31, the fuse on the high-voltage side of the auxiliary transformer is the main protection, and the auxiliary transformer fuse will trip in case of fault; the overcurrent on the high-voltage side of the boost transformer is the backup protection, and the 2DL switch on the high-voltage side of the boost transformer will trip in case of fault.

[0089] The protection scope of the PCS AC protection zone includes the PCS AC side and PCS power module, and is equipped with PCS AC side quick-break overcurrent protection (ACK AC circuit breaker), PCS inverter quick-break overcurrent protection, PCS inverter voltage, frequency protection, power module drive protection, and power module temperature protection.

[0090] For the K21 fault on the PCS AC side, the power module drive protection, PCS AC quick-break, and ACK short-circuit instantaneous protection are the main protections, and the PCS AC overcurrent protection and ACK overcurrent protection are the backup protections. When a fault occurs, the protection action blocks the pulse and trips the ACK AC circuit breaker. The PCS communicates with the BMS to notify the BMS to power off the DC battery cluster. The PCS module temperature is the backup protection. When the module temperature is higher than the set value, the blocking pulse trips the ACK AC circuit breaker. The PCS frequency and voltage are the backup protection. When the frequency and voltage exceed the set value, the blocking pulse trips the ACK AC circuit breaker.

[0091] The protection configuration of each protection area is shown in Table 1:

[0092] Table 1 Protection configuration of each protection area

[0093]

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A regional protection control system for energy storage units based on GOOSE and differential protection, wherein: The energy storage unit includes: a PCS and a battery cluster, connected to a low-voltage bus, the low-voltage bus is connected to a medium-voltage branch bus through a step-up transformer and a high-voltage side switch of the step-up transformer, and the medium-voltage branch bus is connected to the medium-voltage bus as a medium-voltage bus incoming line through an incoming line switch, characterized in that the energy storage unit area protection control system includes: System protection zone, boost protection zone and PCS AC protection zone; the protection range of the system protection zone includes: medium voltage busbar, medium voltage incoming line and high voltage side of boost transformer; the protection range of the boost protection zone includes: high voltage side of boost transformer, low voltage side of boost transformer, auxiliary transformer and PCS AC side; the protection range of the PCS AC protection zone includes: PCS AC side and PCS power module; both the system protection zone and boost protection zone are equipped with differential protection devices; The EMS monitoring system includes: a station control layer and a local control layer; the local control layer adopts optical fiber Ethernet, GOOSE and SV common network, and the protection devices and control devices of the system protection zone, boost protection zone and PCS AC protection zone are connected to the station control layer and the local control layer.

2. According to claim 1, a regional protection control system for energy storage units based on GOOSE and differential protection is characterized in that: The protection devices configured in the system protection zone include: medium voltage bus protection device, unit differential protection device and island protection device; the unit differential protection device, island protection device and PCS inverter use GOOSE communication to access the control layer network; The protection function of the medium-voltage busbar protection device is configured as bus differential protection; the protection function of the unit differential protection device is configured as energy storage unit differential protection and medium-voltage busbar incoming line quick-break overcurrent protection; the protection function of the island protection device is configured as island protection.

3. A storage unit regional protection control system based on GOOSE and differential protection according to claim 1 or 2, characterized in that: The protection devices configured in the boost protection zone include: boost transformer longitudinal differential protection device and auxiliary transformer high voltage fuse; the boost transformer longitudinal differential protection device and PCS inverter use GOOSE communication to access the control layer network; The protection function of the boost transformer longitudinal differential protection device is configured as longitudinal differential protection, boost transformer high-voltage side quick-break overcurrent protection and boost transformer non-electrical quantity protection; the protection function of the auxiliary transformer high-voltage fuse is configured as auxiliary transformer overcurrent protection.

4. The energy storage unit regional protection control system based on GOOSE and differential protection according to claim 1 or 2, characterized in that: The protection devices configured in the PCS AC protection zone include: PCS inverter current protection device, PCS inverter voltage protection device, PCS inverter frequency protection device, PCS inverter island protection device, power module drive protection device and power module temperature protection device; The protection functions of the PCS inverter current protection device are configured as PCS inverter quick-break, overcurrent and insulation protection; The protection functions of the PCS inverter voltage protection device are configured as overvoltage, low voltage, negative sequence voltage protection and synchronization; The protection functions of the PCS inverter frequency protection device are configured as over-frequency, under-frequency protection and synchronization; The protection function of the PCS inverter island protection device is configured as frequency and voltage protection; The protection functions of the AC circuit breaker protection device are configured as PCS AC side quick-break overcurrent protection, short circuit instantaneous, short circuit short delay and overload protection; The protection function of the power module drive protection device is configured as IGBT drive protection; The protection function of the power module temperature protection device is configured as power module temperature protection.

5. A method for controlling regional protection of energy storage units based on GOOSE and differential protection, which is run on the regional protection control system of energy storage units based on GOOSE and differential protection as claimed in any one of claims 1 to 4, characterized in that: In the system protection zone, if the fault point is located on the medium-voltage bus, the bus differential protection is configured as the main protection, and the overcurrent protection on the medium-voltage side of the main transformer on the system side is the backup protection; if the fault point is located on the medium-voltage incoming line, the energy storage unit differential protection is configured as the main protection, and the medium-voltage bus incoming line quick-break overcurrent protection is configured as the backup protection; In the boost protection zone, if the fault point is located on the high-voltage side or low-voltage side of the boost transformer, the boost transformer longitudinal differential protection is configured as the main protection, and the high-voltage side quick-break overcurrent protection of the boost transformer is the backup protection; if the fault point is located on the auxiliary transformer, the auxiliary transformer high-voltage side fuse is the main protection, and the high-voltage side quick-break overcurrent protection of the boost transformer is the backup protection; In the PCS AC protection zone, for the fault point located on the PCS AC side, IGBT drive protection, PCS AC quick-break protection, and AC circuit breaker short-circuit instantaneous protection are configured as main protection, and PCS AC overcurrent protection and AC circuit breaker overcurrent protection are configured as backup protection.

6. The method for regional protection control of energy storage units based on GOOSE and differential protection according to claim 5, characterized in that: If the fault point is located on the medium-voltage bus, the bus protection will be activated during the fault and all the circuit breakers of the medium-voltage bus will be switched; the overcurrent protection on the medium-voltage side of the main transformer on the system side will be activated after a delay and the circuit breaker on the low-voltage side of the main transformer will be tripped; the island protection of the island protection device will be activated, and the island protection device and the PCS inverter will communicate via the control layer network using GOOSE. When the island protection is activated, the PCS inverter pulse will be quickly locked; or the PCS island protection of the PCS inverter island protection device will cause the PCS to shut down after a delay.

7. The method for regional protection control of energy storage units based on GOOSE and differential protection according to claim 5, characterized in that: When the fault point is located on the medium voltage incoming line, the protection action trips the switch between the medium voltage busbar and the medium voltage incoming line, and the switch between the high voltage side of the step-up transformer and the medium voltage incoming line; the unit differential protection device and the PCS inverter communicate via the control layer network using GOOSE, and the PCS inverter pulse is quickly blocked when the energy storage unit differential protection is actuated; The PCS inverter voltage protection and PCS inverter island protection are backup protections, blocking pulses and tripping the AC circuit breaker on the PCS AC side.

8. The method for regional protection control of energy storage units based on GOOSE and differential protection according to claim 5, characterized in that: If the fault point is located on the high-voltage side or low-voltage side of the boost transformer, the protection action will trip the high-voltage side switch of the boost transformer when a fault occurs. The boost transformer longitudinal differential protection device and the PCS inverter communicate via the control layer network using GOOSE. When the boost transformer longitudinal differential protection is in effect, the PCS inverter pulse is quickly blocked and the AC circuit breaker is tripped. PCS inverter voltage protection and PCS inverter island protection are backup protections. If the main protection does not work in case of a fault, the pulse will be blocked and the AC circuit breaker on the PCS AC side will be tripped. And it uses GOOSE to communicate with the boost transformer longitudinal differential protection device through the control layer network to jointly trip the boost transformer side switch.

9. The method for regional protection control of energy storage units based on GOOSE and differential protection according to claim 5, characterized in that: When the fault point is located at the auxiliary transformer, the fuse on the high-voltage side of the auxiliary transformer is the main protection, and the auxiliary transformer fuse will trip when a fault occurs; the quick-break overcurrent protection on the high-voltage side of the boost transformer is the backup protection, and the high-voltage side switch of the boost transformer will trip when a fault occurs.

10. The method for regional protection control of energy storage units based on GOOSE and differential protection according to claim 5, characterized in that: If the fault point is located on the PCS AC side, the protection action blocks the pulse and trips the AC circuit breaker. The PCS communicates with the BMS and notifies the BMS to power off the DC battery cluster. The PCS module temperature is a backup protection. When the module temperature is higher than the set value, the pulse will trip the AC circuit breaker. The PCS frequency and voltage are backup protection. When the frequency and voltage exceed the set value, the pulse will be locked to trip the AC circuit breaker.

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