Two-cluster-sink one-high-voltage box for energy storage and control method thereof

Abstract

The invention discloses a two-cluster-sink one-high-voltage box for energy storage and a control method thereof, the high-voltage box comprises a BAU system-level control module and a high-voltage box assembly, and the high-voltage box assembly comprises a synchronous power-off device and an inter-cluster linkage shunt tripping device; the BAU system-level control module is connected with the high-voltage box assembly through a KA2 broken cluster intermediate relay; and the synchronous power-off device is connected with the inter-cluster linkage shunt tripping device through a BCU distributed control module.

Description

Technical Field

[0001] The present invention belongs to the technical field of power distribution devices, and in particular relates to a two-cluster-one-high-voltage box for energy storage and a control method thereof. Background Art

[0002] The centralized energy storage system consists of multiple battery clusters connected in parallel. Each battery cluster is controlled by a high-voltage box and manages power on and off. When a serious fault occurs in the centralized energy storage system, there is a hidden danger that multiple high-voltage boxes cannot be powered off synchronously. This causes the components in the high-voltage box, such as high-voltage DC contactors and DC fuses, to operate at currents exceeding the rated operating current. This seriously threatens the safety of the energy storage system during operation and maintenance. The internal structure of the high-voltage box is designed with 2 main inputs and 2 main outputs, and 2 isolating switches. The existing components of the high-voltage box occupy a large volume and are relatively expensive. Summary of the invention

[0003] The present invention aims to solve the deficiencies of the prior art and provides the following solutions:

[0004] A two-cluster-to-one high-voltage box for energy storage, comprising: a BAU system-level control module and a high-voltage box assembly, wherein the high-voltage box assembly comprises: a synchronous power-off device and an inter-cluster linkage shunt tripping device;

[0005] The BAU system-level control module is connected to the high-voltage box assembly via the KA2 cluster disconnecting intermediate relay;

[0006] The synchronous power-off device is connected to the inter-cluster linkage shunt tripping device via a BCU distributed control module.

[0007] Preferably, the BAU system-level control module is installed in an electrical room outside the high-voltage box assembly;

[0008] The BAU system-level control module outputs active dry contact signals through the DO and COM pins to control the closing and opening of the coil of the KA2 off-cluster intermediate relay.

[0009] Preferably, the synchronous power-off device comprises: a first current sensor, a first main positive relay, a first main negative relay, a first KA1 cluster disconnect relay, a first BCU distributed control module, a second current sensor, a second main positive relay, a second main negative relay, a second KA1 cluster disconnect relay and a second BCU distributed control module;

[0010] The first current sensor is arranged on a first cluster of positive busbars, and the second current sensor is arranged on a second cluster of positive busbars;

[0011] The first main positive relay is arranged on the first cluster positive busbar, the first main negative relay is arranged on the first cluster negative busbar, the second main positive relay is arranged on the second cluster positive busbar, and the second main negative relay is arranged on the second cluster negative busbar;

[0012] The first main positive relay and the first main negative relay are connected to the first BCU distributed control module through the first KA1 cluster disconnecting relay, and the second main positive relay and the second main negative relay are connected to the second BCU distributed control module through the second KA1 cluster disconnecting relay.

[0013] Preferably, the contact of the KA2 cluster disconnecting intermediate relay is connected to the coils of the two KA1 cluster disconnecting relays to control the closing and opening of the two KA1 cluster disconnecting relays;

[0014] The contacts of each KA1 cluster-breaking relay are respectively connected to the negative poles of the coils of the main positive relay and the main negative relay to control the closing and opening of the main positive relay and the main negative relay;

[0015] The KA2 cluster disconnecting intermediate relay is simultaneously connected in parallel with the coil of the KA1 cluster disconnecting relay of the next high-voltage box.

[0016] Preferably, the inter-cluster linkage shunt tripping device comprises: a QS disconnector, an SHT shunt tripper, an auxiliary contact feedback pin F11, an auxiliary contact feedback pin F12, an auxiliary contact feedback pin F14, a first anti-reverse diode and a second anti-reverse diode;

[0017] The SHT shunt release, the auxiliary contact feedback pin F11, the auxiliary contact feedback pin F12 and the auxiliary contact feedback pin F14 are all installed on the QS disconnector;

[0018] The 24V+ pin of the first BCU distributed control module is connected to the positive electrode of the first anti-reverse diode, the negative electrode of the first anti-reverse diode is connected to the A1 pin of the SHT shunt release, the 24V+ pin of the second BCU distributed control module is connected to the positive electrode of the second anti-reverse diode, and the negative electrode of the second anti-reverse diode is connected to the A1 pin of the SHT shunt release;

[0019] The GND pin of the first BCU distributed control module and the GND pin of the second BCU distributed control module are both connected to the A2 pin of the SHT shunt release.

[0020] The present invention also provides a control method for a two-cluster-one-high-voltage box for energy storage, the control method being used to control any of the above-mentioned high-voltage boxes, comprising the following steps:

[0021] The BCU distributed control module performs cluster current monitoring, SOX calculation, power on / off control and insulation monitoring in real time. When the data monitored by the BCU reaches the serious fault alarm threshold, the BCU distributed control module reports the serious fault to the BAU system-level control module;

[0022] After the BAU system-level control module receives the serious alarm reported by the BCU distributed control module, when the system still detects that the absolute value of the system current I is greater than 0A, it is determined that there is a charge and discharge current, and the judgment conditions include: when the first cluster bus current + the second cluster current is greater than 0A, there is a discharge current; when the first cluster bus current + the second cluster current is less than 0A, there is a charging current;

[0023] When the charge and discharge current lasts for more than 3s, the normal output of the cluster-breaking signal of the BAU system-level control module is a low level, that is, a digital signal 0. According to the fault list, when any cluster needs to execute a high-voltage instruction, the BAU system-level control module outputs a high level, that is, a digital signal 1. At this time, the KA2 cluster-breaking intermediate relay coil is energized, and the normally open contact is converted from the open state 0 to the closed state 1. The KA1 cluster-breaking relay coil in the high-voltage box is energized, and the normally closed contact is converted from the closed state 1 to the open state 0. The negative poles of the coils of the main positive relay and the main negative relay are disconnected synchronously, so that the high-voltage box contactors in the system are powered off synchronously. At the same time, the BCU distributed control module determines whether the contactor is stuck according to the open or closed state of the relay auxiliary contact, and feeds back to the BAU system-level control module;

[0024] After the BCU distributed control module reports the serious fault to the BAU system-level control module, when the BCU distributed control module detects that there is still charging and discharging current in the high-voltage box, and the trigger duration is ≥4s or the relay is in a sticking state, it performs the following inter-cluster linkage shunt tripping action: the shunt tripping pin of the BCU distributed control module inside any high-voltage box outputs a 24V high level, and the 24V electric drive power supply is supplied to the SHT shunt release of the QS isolating switch in N high-voltage boxes through the anti-reverse polarity diode. The shunt tripping coils are energized synchronously to achieve synchronous disconnection of all the QS isolating switches in the high-voltage box. At the same time, the BCU distributed control module determines the tripping state of the QS isolating switch through the auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F12 and reports it to the BAU system-level control module.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention sets a system synchronous power-off device in the energy storage system, and connects the system synchronous power-off device to the high-voltage box of each cluster. In the application, after receiving the power-off command from the BAU through hard-wire drive, the system synchronous power-off device directly controls the relay circuit to power off. All relays in the high-voltage box complete the power-off task synchronously. There is no need to transmit the power-off command to the BCU controller in each cluster of high-voltage boxes in a communication manner through the BAU, and then calculate and execute the power-off command separately. Asynchronous power-off caused by asynchronous, waiting and delay problems in the data transmission and calculation process is avoided, which causes overcurrent accidents. The risk factor of system operation is reduced.

[0027] (2) Furthermore, by setting up an inter-cluster linkage shunt tripping device, when the trigger delay time is ≥4S, or when the relay is in a sticking state, the inter-cluster linkage shunt tripping action is executed, thereby further improving the safety performance of the system operation.

[0028] (3) Furthermore, by simplifying the structure of two-in-one high-voltage box, the internal structure of the high-voltage box merges the two main output circuits into one main output circuit, and one isolating switch is designed. This reduces the design volume of the high-voltage box, reduces the overall cost and loss, and improves the system's production, commissioning, quality inspection and on-site installation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 is an overall circuit diagram of an embodiment of the present invention;

[0031] Figure 2 This is a structural diagram of the high-voltage box assembly according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Embodiment 1

[0035] In this embodiment, if Figure 1 , Figure 2 As shown, a two-cluster-to-one high-voltage box for energy storage includes: a BAU system-level control module and a high-voltage box assembly, wherein the high-voltage box assembly includes: a synchronous power-off device and an inter-cluster linkage shunt tripping device. The BAU system-level control module is connected to the high-voltage box assembly through the KA2 cluster disconnecting intermediate relay; the synchronous power-off device is connected to the inter-cluster linkage shunt tripping device through the BCU distributed control module. The BAU system-level control module is installed in the electrical room outside the high-voltage box assembly; the BAU system-level control module outputs active dry contact signals through the DO and COM pins to control the closing and opening of the coil of the KA2 cluster disconnecting intermediate relay.

[0036] The synchronous power-off device includes: a first current sensor, a first main positive relay, a first main negative relay, a first KA1 cluster-breaking relay, a first BCU distributed control module, a second current sensor, a second main positive relay, a second main negative relay, a second KA1 cluster-breaking relay, and a second BCU distributed control module. The first current sensor is arranged on the first cluster positive bus, and the second current sensor is arranged on the second cluster positive bus; the first main positive relay is arranged on the first cluster positive bus, the first main negative relay is arranged on the first cluster negative bus, the second main positive relay is arranged on the second cluster positive bus, and the second main negative relay is arranged on the second cluster negative bus; the first main positive relay and the first main negative relay are connected to the first BCU distributed control module through the first KA1 cluster-breaking relay, and the second main positive relay and the second main negative relay are connected to the second BCU distributed control module through the second KA1 cluster-breaking relay. The contacts of the KA2 cluster-breaking intermediate relay are connected to the coils of the two KA1 cluster-breaking relays to control the closing and opening of the two KA1 cluster-breaking relays; the contacts of each KA1 cluster-breaking relay are respectively connected to the negative poles of the coils of the main positive relay and the main negative relay to control the closing and opening of the main positive relay and the main negative relay; the KA2 cluster-breaking intermediate relay is simultaneously connected in parallel with the coil of the KA1 cluster-breaking relay of the next high-voltage box.

[0037] The inter-cluster linkage shunt release device includes: a QS disconnector, an SHT shunt releaser, an auxiliary contact feedback pin F11, an auxiliary contact feedback pin F12, an auxiliary contact feedback pin F14, a first anti-reverse diode and a second anti-reverse diode; the SHT shunt releaser, the auxiliary contact feedback pin F11, the auxiliary contact feedback pin F12 and the auxiliary contact feedback pin F14 are all installed on the QS disconnector; the 24V+ pin of the first BCU distributed control module is connected to the positive pole of the first anti-reverse diode, the negative pole of the first anti-reverse diode is connected to the A1 pin of the SHT shunt releaser, the 24V+ pin of the second BCU distributed control module is connected to the positive pole of the second anti-reverse diode, and the negative pole of the second anti-reverse diode is connected to the A1 pin of the SHT shunt releaser; the GND pin of the first BCU distributed control module and the GND pin of the second BCU distributed control module are both connected to the A2 pin of the SHT shunt releaser. When the external applied voltage of the SHT shunt release is 70% to 110% of the rated control voltage, the SHT shunt release can reliably trip the QS disconnector; while the QS disconnector is tripped, it has the rated current capacity of load segmentation; when the QS disconnector is in the "closed" position, the auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F14 are in the conducting state. The auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F12 are respectively connected in parallel to the QS disconnectors of the two BCU distributed control modules to determine the conducting state and non-conducting state of the QS disconnector. When the two BCU distributed control modules detect that the auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F12 are in the conducting state, the QS isolating switch is judged to be in the conducting state, otherwise it is in the non-conducting state; the 24V+ drive of the shunt release pin of the BCU distributed control module is connected to the positive pole of the anti-reverse diode 1N5408, and the negative pole of the anti-reverse diode 1N5408 is connected to the A1 pin of the shunt release SHT, and is connected in parallel with the negative pole of the anti-reverse diode 1N5408 of the next group of the same high-voltage box (or the negative pole of the anti-reverse diode 1N5408 of the next group of the next high-voltage box). The A2 pin of the SHT shunt release is connected to the GND of the shunt release pin of the BCU distributed control module to form a loop, and is connected in parallel with the GND of the shunt release pin of the BCU distributed control module of the next group of the same high-voltage box (or the GND of the BCU shunt release pin of the next group of the next high-voltage box). The shunt trip pins 24V+ of the BCU distributed control modules in all high-voltage boxes are connected in parallel after passing through the anti-reverse diode. After the shunt trips of all high-voltage boxes, the shunt trip pins GND of the BCU distributed control modules in the high-voltage boxes are connected in parallel.

[0038] Embodiment 2

[0039] A control method for a two-cluster-one-high-voltage box for energy storage, comprising the following steps:

[0040] The BCU distributed control module performs cluster current monitoring, SOX calculation, power on and off control, and insulation monitoring in real time. When the data monitored by the BCU reaches the serious fault alarm threshold (serious overvoltage, serious undervoltage, serious overcurrent, serious overtemperature, serious undertemperature, serious pressure difference, serious current difference, insulation failure, etc.), the BCU distributed control module will report the serious fault to the BAU system-level control module.

[0041] After the BAU system-level control module receives the serious alarm reported by the BCU distributed control module, when the system still detects that the absolute value of the system current I is greater than 0A, it determines that there is a charging and discharging current. The judgment conditions include: when the first cluster bus current + the second cluster current is greater than 0A, there is a discharging current; when the first cluster bus current + the second cluster current is less than 0A, there is a charging current.

[0042] When the charge and discharge current lasts for more than 3s, the normal output of the cluster-breaking signal of the BAU system-level control module is a low level, that is, a digital signal 0. According to the fault list, when any cluster needs to execute a high-voltage instruction, the BAU system-level control module outputs a high level, that is, a digital signal 1. At this time, the KA2 cluster-breaking intermediate relay coil is energized, and the normally open contact is converted from the open state 0 to the closed state 1. The KA1 cluster-breaking relay coil in the high-voltage box is energized, and the normally closed contact is converted from the closed state 1 to the open state 0. The negative poles of the coils of the main positive relay and the main negative relay are disconnected synchronously, so that the high-voltage box contactors in the system are powered off synchronously. At the same time, the BCU distributed control module determines whether the contactor is stuck according to the open or closed state of the relay auxiliary contacts (when the contactor coil state is in the open state, the auxiliary contact state is also in the open state, and it is judged that: no adhesion occurs. When the contactor coil state is in the open state and the auxiliary contact state is in the closed state, that is, when the states are inconsistent, it is judged that: the relay is stuck), and feedback is sent to the BAU system-level control module.

[0043] After the BCU distributed control module reports the serious fault to the BAU system-level control module, when the BCU distributed control module detects that there is still charging and discharging current in the high-voltage box, and the trigger duration is ≥4s or the relay is in a sticking state, it executes the following inter-cluster linkage shunt tripping action: the shunt tripping pin of the BCU distributed control module inside any high-voltage box outputs a 24V high level, and the 24V electric drive power supply is supplied to the SHT shunt trippers of the QS isolating switches in N high-voltage boxes through the anti-reverse polarity diode. The shunt tripping coils are energized synchronously to achieve synchronous disconnection of all QS isolating switches in the high-voltage box. At the same time, the BCU distributed control module determines the tripping status of the QS isolating switch through the auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F14 and reports it to the BAU system-level control module.

[0044] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A two-cluster-one-high-voltage box for energy storage, characterized in that: include: BAU system-level control module and high-voltage box assembly, wherein the high-voltage box assembly includes: a synchronous power-off device and an inter-cluster linkage shunt trip device; The BAU system-level control module is connected to the high-voltage box assembly via the KA2 cluster disconnecting intermediate relay; The synchronous power-off device is connected to the inter-cluster linkage shunt tripping device via a BCU distributed control module.

2. According to claim 1, a two-cluster-one-high-voltage box for energy storage, characterized in that: The BAU system-level control module is installed in the electrical room outside the high-voltage box assembly; The BAU system-level control module outputs active dry contact signals through the DO and COM pins to control the closing and opening of the coil of the KA2 disconnect cluster intermediate relay.

3. The two-cluster-one-high-voltage box for energy storage according to claim 1, characterized in that: The synchronous power-off device includes: a first current sensor, a first main positive relay, a first main negative relay, a first KA1 cluster disconnect relay, a first BCU distributed control module, a second current sensor, a second main positive relay, a second main negative relay, a second KA1 cluster disconnect relay and a second BCU distributed control module; The first current sensor is arranged on a first cluster of positive busbars, and the second current sensor is arranged on a second cluster of positive busbars; The first main positive relay is arranged on the first cluster positive busbar, the first main negative relay is arranged on the first cluster negative busbar, the second main positive relay is arranged on the second cluster positive busbar, and the second main negative relay is arranged on the second cluster negative busbar; The first main positive relay and the first main negative relay are connected to the first BCU distributed control module through the first KA1 cluster disconnecting relay, and the second main positive relay and the second main negative relay are connected to the second BCU distributed control module through the second KA1 cluster disconnecting relay.

4. The two-cluster-one-high-voltage box for energy storage according to claim 2, characterized in that: The contacts of the KA2 cluster disconnecting intermediate relay are connected to the coils of the two KA1 cluster disconnecting relays to control the closing and opening of the two KA1 cluster disconnecting relays; The contacts of each KA1 cluster-breaking relay are respectively connected to the negative poles of the coils of the main positive relay and the main negative relay to control the closing and opening of the main positive relay and the main negative relay; The KA2 cluster disconnecting intermediate relay is simultaneously connected in parallel with the coil of the KA1 cluster disconnecting relay of the next high-voltage box.

5. The two-cluster-one-high-voltage box for energy storage according to claim 3, characterized in that: The inter-cluster linkage shunt tripping device comprises: a QS disconnector, an SHT shunt tripper, an auxiliary contact feedback pin F11, an auxiliary contact feedback pin F12, an auxiliary contact feedback pin F14, a first anti-reverse diode and a second anti-reverse diode; The SHT shunt release, the auxiliary contact feedback pin F11, the auxiliary contact feedback pin F12 and the auxiliary contact feedback pin F14 are all installed on the QS disconnector; The 24V+ pin of the first BCU distributed control module is connected to the positive electrode of the first anti-reverse diode, the negative electrode of the first anti-reverse diode is connected to the A1 pin of the SHT shunt release, the 24V+ pin of the second BCU distributed control module is connected to the positive electrode of the second anti-reverse diode, and the negative electrode of the second anti-reverse diode is connected to the A1 pin of the SHT shunt release; The GND pin of the first BCU distributed control module and the GND pin of the second BCU distributed control module are both connected to the A2 pin of the SHT shunt release.

6. A control method for a two-cluster-one-high-voltage box for energy storage, the control method being used to control the high-voltage box according to any one of claims 1 to 5, characterized in that: The following steps are involved: The BCU distributed control module performs cluster current monitoring, SOX calculation, power on / off control and insulation monitoring in real time. When the data monitored by the BCU reaches the serious fault alarm threshold, the BCU distributed control module reports the serious fault to the BAU system-level control module; After the BAU system-level control module receives the serious alarm reported by the BCU distributed control module, when the system still detects that the absolute value of the system current I is greater than 0A, it is determined that there is a charge and discharge current, and the judgment conditions include: when the first cluster bus current + the second cluster current is greater than 0A, there is a discharge current; when the first cluster bus current + the second cluster current is less than 0A, there is a charging current; When the charge and discharge current lasts for more than 3s, the normal output of the cluster-breaking signal of the BAU system-level control module is a low level, that is, a digital signal 0. According to the fault list, when any cluster needs to execute a high-voltage instruction, the BAU system-level control module outputs a high level, that is, a digital signal 1. At this time, the KA2 cluster-breaking intermediate relay coil is energized, and the normally open contact is converted from the open state 0 to the closed state 1. The KA1 cluster-breaking relay coil in the high-voltage box is energized, and the normally closed contact is converted from the closed state 1 to the open state 0. The negative poles of the coils of the main positive relay and the main negative relay are disconnected synchronously, so that the high-voltage box contactors in the system are powered off synchronously. At the same time, the BCU distributed control module determines whether the contactor is stuck according to the open or closed state of the relay auxiliary contact, and feeds back to the BAU system-level control module; After the BCU distributed control module reports the serious fault to the BAU system-level control module, when the BCU distributed control module detects that there is still charging and discharging current in the high-voltage box, and the trigger duration is ≥4s or the relay is in a sticking state, it performs the following inter-cluster linkage shunt tripping action: the shunt tripping pin of the BCU distributed control module inside any high-voltage box outputs a 24V high level, and the 24V electric drive power supply is supplied to the SHT shunt release of the QS isolating switch in N high-voltage boxes through the anti-reverse polarity diode. The shunt tripping coils are energized synchronously to achieve synchronous disconnection of all the QS isolating switches in the high-voltage box. At the same time, the BCU distributed control module determines the tripping state of the QS isolating switch through the auxiliary contact feedback pin F11 and the auxiliary contact feedback pin F12 and reports it to the BAU system-level control module.

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