CN211556956U - High-reliability direct-current power supply for transformer substation - Google Patents

High-reliability direct-current power supply for transformer substation Download PDF

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Publication number
CN211556956U
CN211556956U CN201922056772.8U CN201922056772U CN211556956U CN 211556956 U CN211556956 U CN 211556956U CN 201922056772 U CN201922056772 U CN 201922056772U CN 211556956 U CN211556956 U CN 211556956U
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China
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direct current
diode
module
bus
direct
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Inventor
朱开成
王嘉曦
沈梦瀛
钱卓蕾
张磊
高泓
丁昊
韩磊
王国明
吴宏刚
陈亮
潘金梅
李民
刘志军
陈培琦
祝丽娟
卢毅
童大中
鲁水林
周开运
王玥
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Huzhou Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
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Huzhou Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
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Abstract

The utility model discloses a transformer substation uses high reliability DC power supply. In order to overcome the defects of series connection of battery packs of a direct current power supply system, poor reliability and single lagging effect in the prior art; when the AC is lost and the DC load is short-circuited, the short-circuit current can not be cut off. The utility model adopts a bus, an AC/DC module, a breaker, a DC load, a DC/DC module and a battery module; the bus at the input end of the AC/DC module is an alternating current bus, the bus at the output end of the AC/DC module is a direct current bus, the direct current bus is connected with a direct current load, and the breaker is arranged on the direct current bus; the battery module comprises a plurality of battery packs connected in parallel, and each battery pack is connected with a DC/DC module; the DC/DC module is connected with the direct current bus; and guide elements are arranged between the battery pack and the direct current bus and between the battery packs. The supply of a direct current power supply is ensured, the problem of the lagging effect of a single battery is solved, and the reliability is improved; when short circuit occurs, the circuit breaker is provided with cut-off current, and the safety is improved.

Description

High-reliability direct-current power supply for transformer substation
Technical Field
The utility model relates to a direct current power supply system field of transformer substation especially relates to a transformer substation uses high reliability direct current power supply.
Background
The power supply of the direct current system is the power supply of relay protection, automatic control and other devices in a transformer substation, the storage battery pack as the only standby power supply for normal work of the direct current system is the core component of the direct current system, and the power supply reliability of the storage battery pack plays an important role in safe operation of the power system.
At present, the power supply scheme of the dc system is as follows: 380V alternating current is converted into 110V or 220V direct current to supply power to a system, meanwhile, a group of storage batteries are used for standby, and when the alternating current is abnormal, the storage batteries supply power. The standby power supply only has one storage battery pack, and when the alternating current is abnormal, if the storage battery pack also fails, the direct current system loses the power supply; the replacement process is complicated when the battery is replaced. The storage battery pack is formed by connecting batteries in series, and a single-section fault can cause the fault of the whole pack, namely, the single-section lag effect. During the charge and discharge test, various indexes cannot be acquired in real time; the real-time monitoring function is incomplete, the running state and the performance change trend of the storage battery cannot be completely mastered, early warning cannot be timely performed, and the hidden trouble of the fault can be eliminated. If the direct current load is short-circuited, the breaker trip current cannot be supplied and the short-circuit current cannot be cut off because the DC/DC supply current has an upper limit.
For example, a "substation DC power supply system" disclosed in chinese patent literature, whose publication number "CN 203481883U" includes a battery module group, where the battery module group includes a plurality of battery modules connected in parallel, and each of the battery modules includes an AC/DC charging module, a lithium iron phosphate battery pack, and a DC/DC boost module; the transformer substation direct-current power supply system also comprises a power supply current adjusting module, a charging and discharging current adjusting module, a protection device and a battery management module; the power supply current adjusting module, the charging and discharging current adjusting module, the protection device and the battery management module are electrically connected with the storage battery module group. Although the power supply system adopts a structure of parallel battery modules, if a direct current load is short-circuited, the DC/DC power supply current has an upper limit, so that the tripping current of a breaker cannot be provided, the short-circuit current cannot be cut off, and the response speed of the voltage of a support bus is also influenced by the DC/DC performance.
SUMMERY OF THE UTILITY MODEL
The utility model mainly solves the problems of the prior art that the battery pack of the DC power supply system is connected in series, the reliability is poor, and the single lagging effect exists; when the direct current load is short-circuited, the short-circuit current can not be cut off; the high-reliability direct-current system for the transformer substation solves the problem that when an alternating current is abnormal and a storage battery pack also fails, the direct-current system loses power and the single battery module of the direct-current power supply system has a lagging effect, and solves the problem that short-circuit current cannot be cut off when a direct-current load is in short circuit.
The above technical problem of the present invention can be solved by the following technical solutions:
the utility model comprises a bus, an AC/DC module, a breaker and a DC load; the bus at the input end of the AC/DC module is an alternating current bus, the bus at the output end of the AC/DC module is a direct current bus, the direct current bus comprises a plurality of direct current outgoing lines, each direct current outgoing line is connected with a direct current load, and the breaker is arranged on the direct current outgoing line; the direct current power supply is characterized by further comprising a bidirectional DC/DC module and a battery module, wherein the battery module comprises a plurality of battery packs connected in parallel, and each battery pack is connected with one bidirectional DC/DC module; the bidirectional DC/DC module is connected with the direct current bus; and a guide element is arranged between the battery pack and the direct current bus.
The scheme that battery packs are connected in parallel instead of in series is adopted, one battery module comprises a plurality of battery packs, the battery packs are mutually standby, when the battery packs break down, power can be maintained even if only one group of storage batteries are left, and power loss is avoided. In consideration of reality, one battery module includes 3 or 4 battery packs. The battery packs are connected in parallel instead of in series, the number of corresponding storage batteries in each battery pack is reduced, and in consideration of reality, each battery pack comprises 18 storage batteries when 3 battery packs are provided, and each battery pack comprises 13 storage batteries when 4 battery packs are provided; the single lag effect is weakened, the failure probability is reduced, and the reliability of the direct current system is improved. The parallel battery pack is adopted, so that the failed battery pack can be directly replaced when the battery pack fails, and the normal work of a direct current system is not influenced; the replacement process is simple, the spare battery does not need to be installed firstly, the failed battery pack is replaced, and then the spare battery is detached. The process of replacing the standby battery pack is simple, convenient and safe.
A guide element is arranged between the direct current bus and the battery pack, the battery pack is connected in series through the guide element and is connected to the direct current bus, and when a direct current load is in short circuit, on-off current is provided for the circuit breaker, so that a direct current system is protected, and the reliability and the safety of the direct current system are improved; the series battery is directly connected with the direct current bus, and can instantly provide voltage when the direct current bus is in voltage loss until the DC/DC starts to work to support the voltage, so that the power supply reliability of the direct current load is improved.
Preferably, the guiding element is a diode, and the diode comprises a diode D5 and a diode D8; the battery packs are sequentially connected in series to form a series battery pack; the anode of the diode D5 is connected with the negative bus of the direct current bus, and the cathode of the diode D5 is connected with the negative electrode of the series battery pack; the anode of the diode D8 is connected to the anode of the series battery, and the cathode of the diode D8 is connected to the positive bus of the dc bus. Because of the reverse cut-off characteristic of the diode, when the direct-current bus voltage is normal, the series circuit of the battery pack is not conducted; when the direct-current load of the direct-current bus is in short circuit, the voltage drop of the direct-current bus is 0, the series circuit is conducted, the on-off current is provided for the circuit breaker, the circuit breaker can normally act when the direct-current load is in short circuit, and the reliability and the safety of a direct-current system are guaranteed.
Preferably, the direct current power supply further comprises a monitoring unit and an upper computer, wherein the monitoring unit comprises a monitoring chip, and a voltage sensor, a temperature sensor and a current sensor which are connected with the monitoring chip; the monitoring chip is connected with the control end of the DC/DC module and is connected with an upper computer through a communication protocol. The monitoring unit monitors current, voltage and temperature data of the battery module, and the monitoring chip uploads the data to the upper computer, so that the data can be recorded, stored and observed conveniently. The monitoring unit uses a touch-sensitive microcomputer monitor, model KXT 05. The monitoring chip is connected with the upper computer and the control end of the DC/DC module, and is convenient for remote control of workers.
Preferably, the bidirectional DC/DC module is a bidirectional DC/DC module with isolation; the bidirectional DC/DC module comprises a direct current step-down circuit with isolation and a direct current step-up circuit with isolation; the direct-current voltage reduction circuit and the direct-current voltage boosting circuit have the same circuit structure, and are reversely connected in parallel; the input end of the direct current voltage reduction circuit is connected with the output end of the direct current booster circuit, and the output end of the direct current voltage reduction circuit is connected with the input end of the direct current booster circuit. The bidirectional DC/DC module is selected, the DC/DC module can charge the battery pack from the direct current bus and can discharge from the battery pack to the direct current bus through the DC/DC module, and the system is simple in structure and complete in function. The charging and discharging of the battery pack by the bidirectional DC/DC module are realized according to the difference between the output voltage of the bidirectional DC/DC module and the voltage of the direct-current bus and the switching state of the locking switch S1, and the bidirectional DC/DC module does not need program control, has low time delay and is quick in response.
Preferably, the bidirectional DC/DC module further includes a diode D6, a diode D7, a latching switch S1, and an interlock switch S2; a first end of the interlock switch S2 is connected with a positive bus of the direct-current bus, a second end of the interlock switch S2 is connected with a first end of the latching switch S1, and a second end of the latching switch S2 is connected with a positive input end of the direct-current step-down circuit; the negative input end of the direct current voltage reduction circuit is connected with the negative bus of the direct current bus, the positive output end of the direct current voltage reduction circuit is connected with the anode of the diode D6, the cathode of the diode D6 is connected with the positive end of the battery pack, and the negative output end of the direct current voltage reduction circuit is connected with the negative end of the battery pack; the input end of the direct current booster circuit is connected with the battery pack, the positive output end of the direct current booster circuit is connected with the anode of the diode D7, the cathode of the diode D7 is connected with the second end of the interlock switch S2, and the negative output end of the direct current booster circuit is connected with the negative bus of the direct current bus. Diode D6 and diode D7 act as a guide to prevent the danger of current back-flow. An interlocking switch S2 is arranged between the bidirectional DC/DC module and the direct current bus, a locking switch S1 is arranged at the input end of the direct current voltage reduction circuit, the locking switch S1 controls the charging locking of the battery pack, and the interlocking switch S2 ensures that only one battery pack carries out charging and discharging work when the battery pack is charged and discharged remotely, can separately control the charging and discharging states of the battery packs, realizes the mutual locking function between the battery packs, and ensures that only one battery pack is in the charging and discharging state.
Preferably, the isolated dc voltage reduction circuit includes a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a diode D1, a diode D2, a diode D3, a diode D4, an inductor L1, a capacitor C1, and a transformer T1; the first end of the second controllable switch is used as the positive input end of the direct-current voltage reduction circuit, the second end of the second controllable switch is connected with the first end of the first controllable switch, and the second end of the first controllable switch is used as the negative input end of the direct-current voltage reduction circuit; the first end of the fourth controllable switch is connected with the first end of the second controllable switch, the second end of the fourth controllable switch is connected with the first end of the third controllable switch, and the second end of the third controllable switch is connected with the second end of the first controllable switch; the cathode of the diode D1 is connected with the anode of the diode D2; the cathode of the diode D3 is connected with the anode of the diode D4; the anode of the diode D1 is connected with the anode of the diode D3, and the cathode of the diode D4 is connected with the cathode of the diode D2; the first input end of the primary side of the transformer T1 is connected with the second end of the second switching tube, the second input end of the primary side of the transformer T1 is connected with the second end of the fourth switching tube, the first output end of the secondary side of the transformer T1 is connected with the anode of the diode D2, and the second output end of the secondary side of the transformer T1 is connected with the anode of the diode D4; the first input end of the primary side of the transformer T1 and the first output end of the primary side of the transformer T1 are homonymous ends; the anode of the diode D3 is connected with the first end of the capacitor C1, the cathode of the diode D4 is connected with the first end of the inductor L1, and the second end of the inductor L1 is connected with the second end of the capacitor C1; the first end of the capacitor C1 is used as the negative output end of the DC step-down circuit, and the second end of the capacitor C1 is used as the positive output end of the DC step-down circuit. An inductor L1 stabilizes current, and a capacitor C1 stabilizes voltage. The direct current voltage reduction circuit charges the battery pack, the AC/DC module converts alternating current into direct current voltage of 110V, starting voltage of the direct current voltage reduction module is 109V, and the direct current voltage reduction circuit reduces the voltage of 110V of the direct current bus to be lower so as to charge batteries in the battery pack. Because the direct current boost circuit and the direct current step-down circuit have the same structure and are reversely connected in parallel, the output voltage of the direct current boost circuit is 108V, and when the direct current bus supplies power normally, the voltage of the direct current bus is 110V. When the voltage of the direct current bus is greater than the charging starting voltage of the DC/DC module and the charging function is not locked, the direct current bus charges the battery pack; and when the voltage of the direct current bus is less than the voltage of the output end of the DC/DC module, the battery pack discharges. The circuit has simple structure, does not need program control, is realized by voltage difference, has low time delay and high response speed. And the transformer is used for isolating the electrical connection between the battery pack and the direct current bus, so that the safety is improved.
Preferably, the locking switch S1, the interlock switch S2 and the controllable switch are all electromagnetic switches. And an electromagnetic switch is used, so that the control mode is simple and the cost is low.
Preferably, the latching switch S1 and the controllable switch are N-channel MOS transistors, first terminals of the latching switch S1 and the controllable switch are drains of the MOS transistors, and second terminals of the latching switch S1 and the controllable switch are sources of the MOS transistors. The N-channel MOS tube is used as a switch, so that the cost is low, the control mode is simple, and the anti-interference capability is strong.
Preferably, each battery pack comprises 18 storage batteries connected in series. The number of the storage batteries of a single battery pack is reduced to 18, the number of the storage batteries of each battery pack is reduced, the probability of failure of the battery pack caused by single lagging effect is reduced, and the reliability and the safety of the direct-current power supply are improved.
The utility model has the advantages that:
1. the parallel battery pack is used, so that the probability of failure caused by single lagging effect is reduced, the probability of failure of the battery module is reduced, and the reliability of the direct-current power supply is improved.
2. The diode is arranged between the direct current bus and the battery pack, and is cut off under a general condition, and the cut-off current is provided for the circuit breaker when a load is in a short circuit, so that the safety and the reliability of the direct current power supply are ensured.
3. The series battery is directly connected with the direct current bus, and can instantly provide voltage when the direct current bus is in voltage loss until the DC/DC starts to work to support the voltage, so that the power supply reliability of the direct current load is improved.
4. The parallel battery pack is adopted, so that no extra equipment or power failure is needed during fault replacement, the process of replacing the battery pack is simple, and the efficiency is improved.
5. The monitoring unit monitors the state of the battery module, is connected with the upper computer, remotely controls the charging and discharging of the battery pack, saves labor and avoids errors of manual detection.
6. The bidirectional DC/DC module is used for realizing the charge and discharge function according to the voltage difference and the switching state of the locking switch S1, and has the advantages of no need of program control, high response speed and low time delay.
7. The bidirectional DC/DC module is isolated by the transformer, so that the electrical connection between the battery pack and the direct current bus is isolated, and the safety is improved.
Drawings
Fig. 1 is a block diagram of a circuit principle connection structure of the present invention.
Fig. 2 is a block diagram of a connection structure of a monitoring unit according to the present invention.
Fig. 3 is a circuit diagram of a bidirectional DC/DC module according to the present invention.
In the figure, 1, an AC/DC module, 2, a circuit breaker, 3, a direct current load, 4, a battery pack, 5, a DC/DC module, 51, a direct current voltage reduction circuit, 52, a direct current voltage boosting circuit, 6 battery modules, 7 a monitoring unit, 71, a monitoring chip, 72, a voltage sensor, 73, a temperature sensor, 74, a current sensor and 8, an upper computer.
Detailed Description
The technical solution of the present invention is further specifically described below by way of examples and with reference to the accompanying drawings.
Example (b):
a high-reliability direct-current power supply for a transformer substation is shown in figure 1 and comprises a bus, an AC/DC module 1, a circuit breaker 2, a direct-current load 3, a DC/DC module 5, a battery module 6, a monitoring unit 7 and an upper computer 8.
The bus at the input end of the AC/DC module 1 is an alternating current bus, and the bus at the output end of the AC/DC module 1 is a direct current bus. The alternating current bus comprises a live line L and a zero line N, and the direct current bus comprises a positive bus M + and a negative bus M-. The direct current bus comprises a plurality of direct current outgoing lines, each direct current outgoing line is connected with a direct current load 3, and the circuit breaker 2 is arranged between the direct current outgoing line and the direct current load 3. When one breaker 2 is in open circuit protection, the direct current loads of other direct current outgoing lines can still continue to work. The battery module 6 is connected to the DC/DC module 5, and the DC/DC module 5 is connected to the DC bus. The monitoring unit 7 is connected with the control ends of the battery module 6 and the DC/DC module 5, and the monitoring unit 7 is in communication connection with the upper computer 8 through a communication protocol.
The battery module 6 comprises a plurality of battery packs 4 connected in parallel, each battery pack 4 is connected with a DC/DC module 5, and the DC/DC modules 5 are connected with a direct current bus. Each battery pack includes 18 batteries connected in series. The number of the storage batteries of a single battery pack is reduced to 18, the number of the storage batteries in each battery pack is reduced, the probability of failure of the battery pack due to single lag effect is reduced, and the reliability of the direct-current power supply is improved.
In the embodiment, the parallel battery pack 4 is adopted, so that when the battery pack 4 fails, the failed battery pack can be directly replaced without influencing the normal work of a direct current system; the replacement process is simple, the spare battery does not need to be installed firstly, the failed battery pack is replaced, and then the spare battery is detached. The process of replacing the standby battery pack is simple, convenient and safe, and the working efficiency is improved.
Instead of a series arrangement using parallel connection of the battery packs 4, one battery module 6 comprises three or four battery packs 4 connected in parallel, in this embodiment three battery packs 4 connected in parallel. The battery packs 4 are mutually standby, and when one or more battery packs 4 are in failure, even if only one group of storage batteries is left, the power can be maintained, and the power can not be lost. When the alternating current is abnormal and a part of battery packs 4 in the battery modules 6 are in failure, the direct current system supplies power according to the old power supply; failure of a single or partial battery pack 4 in a battery module 6 does not cause the entire battery module 6 to fail; the number of storage batteries in each battery pack is reduced, so that the single lagging effect is weakened, the failure probability is reduced, and the reliability of a direct current system is improved; the series battery is directly connected with the direct current bus, and can instantly provide voltage when the direct current bus is in voltage loss until the DC/DC starts to work to support the voltage, so that the power supply reliability of the direct current power supply is improved.
A diode is provided between the battery module 6 and the dc bus. In the present embodiment, the diodes include a diode D5 and a diode D8.
The battery packs are sequentially connected in series to form a series battery pack. In the present embodiment, the battery packs from the side near the AC/DC module 1 to the side near the circuit breaker 2 are the first battery pack, the second battery pack, and the third battery pack in this order. The positive electrode of the first battery pack is connected with the negative electrode of the second battery pack, and the positive electrode of the second battery pack is connected with the negative electrode of the third battery pack; the anode of the diode D5 is connected with the negative bus M-of the direct current bus, and the cathode of the diode D5 is connected with the negative electrode of the first battery pack; the anode of the diode D8 is connected to the positive electrode of the third battery pack, and the cathode of the diode D8 is connected to the positive bus M + of the DC bus.
Because of the reverse blocking characteristic of the diode, when the direct-current bus voltage is normal, the series circuit of the battery pack 4 is not turned on; when the direct current load 3 of the direct current bus is in short circuit, the voltage drop of the direct current bus is zero, the series circuit of the battery pack 4 is conducted, the cut-off current is provided for the circuit breaker, the circuit breaker can normally act when the direct current load is in short circuit, and the reliability and the safety of a direct current system are guaranteed.
As shown in fig. 2, the monitoring unit 7 includes a monitoring chip 71, and a voltage sensor 72, a temperature sensor 73, and a current sensor 74 connected to the monitoring chip 71; the voltage sensor 72, the temperature sensor 73 and the current sensor 74 are connected to the battery module 6, the monitoring chip 71 is connected to the control end of the DC/DC module 5, and the monitoring chip 71 is connected to the upper computer 8 through a communication protocol.
The monitoring unit 7 monitors the current, voltage and temperature data of the battery module 6 through the current sensor 74, the voltage sensor 72 and the temperature sensor 73 respectively, and the monitoring chip 71 uploads the data to the upper computer 8, so that the data is convenient to record, store and observe. The manpower is saved, the monitoring data is read, the manual error is avoided, and the manpower is saved. The monitoring unit 8 uses a touch microcomputer monitor model KXT 05. The monitoring chip 71 is connected with the control ends of the upper computer 8 and the DC/DC module 5, so that the battery module 6 can be conveniently and remotely controlled by a worker to carry out charging and discharging experiments, manpower is saved, and the control is convenient.
As shown in fig. 3, the bidirectional DC/DC module 5 is a bidirectional DC/DC module 5 with isolation. The bidirectional DC/DC module 5 includes a DC step-down circuit 51 with isolation, a DC step-up circuit 52 with isolation, a diode D6, a diode D7, a latching switch S1, and an interlock switch S2. The dc step-down circuit 51 and the dc step-up circuit 52 have the same circuit configuration, and the dc step-up circuit 52 and the dc step-down circuit 51 are connected in anti-parallel. In this embodiment, the latching switch S1 is an N-channel MOS transistor, and the interlock switch S2 is an electromagnetic switch.
The dc voltage reduction circuit 51 includes a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a diode D1, a diode D2, a diode D3, a diode D4, an inductor L1, a capacitor C1, and a transformer T1. The first controllable switch is an N-channel MOS transistor Q1 with a protection diode, the second controllable switch is an N-channel MOS transistor Q2 with a protection diode, the third controllable switch is an N-channel MOS transistor Q3 with a protection diode, and the fourth controllable switch is an N-channel MOS transistor Q4 with a protection diode.
The drain of the MOS transistor Q2 is used as the positive input terminal of the dc voltage-reducing circuit 51, the source of the MOS transistor Q2 is connected to the drain of the MOS transistor Q1, and the source of the MOS transistor Q1 is used as the negative input terminal of the dc voltage-reducing circuit 51. The drain of MOS pipe Q4 is connected with the drain of MOS pipe Q2, the source of MOS pipe Q4 is connected with the drain of MSO pipe Q3, and the source of MOS pipe Q3 is connected with the source of MOS pipe Q1. The cathode of the diode D1 is connected with the anode of the diode D2, and the cathode of the diode D3 is connected with the anode of the diode D4; the anode of the diode D1 is connected to the anode of the diode D3, and the cathode of the diode D4 is connected to the cathode of the diode D2. The first input end of the primary side of the transformer T1 is connected with the source electrode of the MOS tube Q2, the second input end of the primary side of the transformer T1 is connected with the source electrode of the MOS tube Q4, the first output end of the secondary side of the transformer T1 is connected with the anode of the diode D2, and the second output end of the secondary side of the transformer T1 is connected with the anode of the diode D4; the first input terminal of the primary side of transformer T1 and the first output terminal of the primary side of transformer T1 are homonymous terminals.
The anode of the diode D3 is connected with the first end of the capacitor C1, the cathode of the diode D4 is connected with the first end of the inductor L1, and the second end of the inductor L1 is connected with the second end of the capacitor C1; a first terminal of the capacitor C1 serves as a negative output terminal of the dc step-down circuit 51, and a second terminal of the capacitor C1 serves as a positive output terminal of the dc step-down circuit 51.
The DC voltage reduction circuit 51 charges the battery pack, the AC/DC module 1 converts AC power to 110V DC voltage, and the DC voltage reduction circuit 51 reduces the 110V voltage of the DC bus to a lower level to charge the battery in the battery pack 4. The circuit structure is simple, the charging does not need program control, the charging is realized through the voltage difference and the switch state of the locking switch S1, the time delay is low, and the response speed is high. The N-channel MOS tube is used as a switch, so that the cost is low, the control mode is simple, and the anti-interference capability is strong. And the transformer is used for isolating the electrical connection between the battery pack and the direct current bus, so that the safety is improved.
The dc boost circuit 52 includes a fifth controllable switch, a sixth controllable switch, a seventh controllable switch, an eighth controllable switch, a diode D9, a diode D10, a diode D11, a diode D12, an inductor L2, a capacitor C2, and a transformer T2. The fifth controllable switch is an N-channel MOS transistor Q5 with a protection diode, the sixth controllable switch is an N-channel MOS transistor Q6 with a protection diode, the seventh controllable switch is an N-channel MOS transistor Q7 with a protection diode, and the eighth controllable switch is an N-channel MOS transistor Q8 with a protection diode.
The drain of the MOS transistor Q6 is used as the positive input terminal of the dc boost circuit 52, the source of the MOS transistor Q6 is connected to the drain of the MOS transistor Q5, and the source of the MOS transistor Q5 is used as the negative input terminal of the dc boost circuit 52. The drain of MOS pipe Q8 is connected with the drain of MOS pipe Q6, the source of MOS pipe Q8 is connected with the drain of MSO pipe Q7, and the source of MOS pipe Q7 is connected with the source of MOS pipe Q5. The cathode of the diode D9 is connected with the anode of the diode D10, and the cathode of the diode D11 is connected with the anode of the diode D12; the anode of the diode D9 is connected to the anode of the diode D11, and the cathode of the diode D12 is connected to the cathode of the diode D10. The first input end of the primary side of the transformer T1 is connected with the source electrode of the MOS tube Q6, the second input end of the primary side of the transformer T1 is connected with the source electrode of the MOS tube Q8, the first output end of the secondary side of the transformer T1 is connected with the anode of the diode D6, and the second output end of the secondary side of the transformer T1 is connected with the anode of the diode D12; the first input terminal of the primary side of transformer T1 and the first output terminal of the primary side of transformer T1 are homonymous terminals.
The anode of the diode D11 is connected with the first end of the capacitor C2, the cathode of the diode D12 is connected with the first end of the inductor L2, and the second end of the inductor L2 is connected with the second end of the capacitor C2; a first terminal of the capacitor C2 serves as a negative output terminal of the dc boost circuit 52, and a second terminal of the capacitor C2 serves as a positive output terminal of the dc boost circuit 52.
The output voltage of the direct current booster circuit is 108V, and when the direct current bus supplies power normally, the voltage of the direct current bus is 110V. When the voltage of the direct current bus is greater than the charging starting voltage of the DC/DC module 5 and the charging function is not locked, the direct current bus charges the battery pack; when the voltage of the DC bus is less than the voltage at the output of the DC/DC module 5, the battery pack discharges. The circuit has simple structure, does not need program control, is realized by voltage difference, has low time delay and high response speed. The N-channel MOS tube is used as a switch, so that the cost is low, the control mode is simple, and the anti-interference capability is strong. And the transformer is used for isolating the electrical connection between the battery pack and the direct current bus, so that the safety is improved.
The first end of the interlock switch S2 is connected to the positive bus M + of the dc bus, the second end of the interlock switch S2 is connected to the drain of the latch switch S1, and the source of the latch switch S2 is connected to the positive input of the dc voltage step-down circuit 51, i.e., the drain of the MOS transistor Q2. The negative input end of the direct current voltage reduction circuit 51, namely the source electrode of the MOS transistor Q1, is connected with the negative bus M of the direct current bus, the positive output end of the direct current voltage reduction circuit 51, namely the second end of the capacitor C1, is connected with the anode of the diode D6, the cathode of the diode D6 is connected with the positive end of the battery pack 4, and the negative output end of the direct current voltage reduction circuit 51, namely the first end of the capacitor C1 is connected with the negative end of the battery pack 4. The input end of the direct current booster circuit 51 is connected with the battery pack 4, namely the drain electrode of the MOS tube Q6 is connected with the positive electrode end of the battery pack 4, and the source electrode of the MOS tube Q5 is connected with the negative electrode end of the battery pack 4; the positive output terminal of the dc boost circuit 52, i.e., the second terminal of the capacitor C2, is connected to the anode of the diode D7, the cathode of the diode D7 is connected to the second terminal of the interlock switch S2, and the negative output terminal of the dc boost circuit 52, i.e., the first terminal of the capacitor C2, is connected to the negative bus M-of the dc bus.
The locking switch S1 controls the charging locking of the battery pack, and the interlocking switch S2 ensures that only one battery pack performs charging and discharging work when the battery pack is charged and discharged remotely.
The bidirectional DC/DC module 5 is selected, the DC/DC module 5 can charge the battery pack 4 from the direct current bus and can discharge from the battery pack 4 phase direct current bus through the DC/DC module 5, and the bidirectional DC/DC module is simple in structure and complete in function. The bidirectional DC/DC module 5 uses a transformer to isolate the electrical connection between the battery pack 4 and the DC bus, thereby improving the safety. The charging and discharging of the battery pack 4 are realized through the voltage difference between the output voltage of the bidirectional DC/DC module 5 and the voltage of the direct current bus, program control is not needed, the battery pack can discharge through the bidirectional DC/DC module 5 at the moment of power failure of the direct current bus, and the bidirectional DC/DC module is low in delay and high in response speed.
Under normal conditions, the battery pack 4 is automatically charged:
the 380V alternating current power supply is converted into 110V direct current voltage through the AC/DC module 1 and is output to the direct current bus; meanwhile, the direct-current voltage 110V at the direct-current bus reaches the charge starting voltage 109V by the bidirectional DC/DC module 5, and the charging function of the bidirectional DC/DC module 5 is started to charge the battery pack 4. The charging process does not need to be monitored and controlled, and the charging process is automatically carried out under the condition that the voltage of the direct-current bus reaches the charging starting voltage. The output voltage 108V of the bidirectional DC/DC module 5 is lower than the voltage of the direct current bus, and the discharging function is closed.
In the case of an ac anomaly, the battery pack 4 automatically discharges:
when the voltage of the direct current bus is reduced due to abnormal alternating current, the output voltage 108V of the bidirectional DC/DC module 5 is larger than the voltage of the direct current bus, the discharging function is rapidly started, the battery pack 4 automatically discharges to supply power to the direct current bus, and the discharging process does not need to be monitored and controlled. Meanwhile, the voltage at the DC bus is not sufficient to reach the charging start voltage 109V of the bidirectional DC/DC module 5, and the charging function of the bidirectional DC/DC module 5 is turned off.
The bidirectional DC/DC module 5 is selected, the DC/DC module 5 can charge the battery pack 4 from the direct current bus and discharge from the battery pack 4 phase direct current bus through the DC/DC module 5, the charging and discharging state of the battery pack is controlled by the voltage difference between the voltage output by the bidirectional DC/DC module and the voltage of the direct current bus, program control is not needed, when the direct current bus loses power, the battery pack can discharge through the bidirectional DC/DC module, and response time is fast and delay is low. The whole direct current system is simple in structure and complete in function. Be provided with the interlock switch between two-way DC/DC module 5 and direct current bus, be provided with the shutting switch at the input of direct current step-down module, the shutting switch control battery pack the shutting of charging, the interlock switch is when long-range charge-discharge, guarantees that only a set of group battery carries out charge-discharge work, can separately control the charge-discharge state of each group battery, realizes the function of shutting each other between each group battery, guarantees that only a group battery is in charge-discharge state.
The utility model discloses an use parallelly connected group battery, reduced the quantity of battery in every group battery, reduced because the probability that single effect behind after breaks down, reduced the probability that battery module broke down, improved DC power supply's reliability. When the fault is replaced, no extra equipment or power failure is needed, the process of replacing the battery pack is simple, and the efficiency is improved. The diode is arranged between the direct current bus and the battery pack, and is cut off under a general condition, and the cut-off current is provided for the circuit breaker when a load is in a short circuit, so that the safety and the reliability of the direct current power supply are ensured. The monitoring unit monitors the state of the battery module, is connected with the upper computer, remotely controls the charging and discharging of the battery pack, saves labor and avoids errors of manual detection. The bidirectional DC/DC module is used, realizes the charge and discharge function through voltage difference, has high corresponding speed and no delay, and has simple structure, complete functions and low cost.

Claims (9)

1. A high-reliability direct-current power supply for a transformer substation comprises a bus, an AC/DC module (1), a circuit breaker (2) and a direct-current load (3); the bus at the input end of the AC/DC module (1) is an alternating current bus, the bus at the output end of the AC/DC module (1) is a direct current bus, the direct current bus comprises a plurality of direct current outgoing lines, each direct current outgoing line is connected with a direct current load (3), and the breaker (2) is arranged on the direct current outgoing lines; the direct current power supply is characterized by further comprising a bidirectional DC/DC module (5) and a battery module (6), wherein the battery module (6) comprises a plurality of battery packs (4) connected in parallel, and each battery pack (4) is connected with one bidirectional DC/DC module (5); the bidirectional DC/DC module (5) is connected with the direct current bus; a guide element is arranged between the battery pack (4) and the direct current bus.
2. The high-reliability direct-current power supply for the substation of claim 1, wherein the guiding element is a diode, and the diode comprises a diode D5 and a diode D8; the battery packs (4) are sequentially connected in series to form a series battery pack; the anode of the diode D5 is connected with the negative bus of the direct current bus, and the cathode of the diode D5 is connected with the negative electrode of the series battery pack; the anode of the diode D8 is connected to the anode of the series battery, and the cathode of the diode D8 is connected to the positive bus of the dc bus.
3. The high-reliability direct-current power supply for the substation according to claim 1, wherein the direct-current power supply further comprises a monitoring unit (7) and an upper computer (8); the monitoring unit (7) comprises a monitoring chip (71), and a voltage sensor (72), a temperature sensor (73) and a current sensor (74) which are connected with the monitoring chip (71); the monitoring device is characterized in that the voltage sensor (72), the temperature sensor (73) and the current sensor (74) are connected to the battery module (6), the monitoring chip (71) is connected with the control end of the DC/DC module (5), and the monitoring chip (71) is connected with the upper computer (8) through a communication protocol.
4. A high reliability DC power supply for substations according to claim 1 or 3, characterized in that said bidirectional DC/DC module (5) is a bidirectional DC/DC module (5) with isolation; the bidirectional DC/DC module (5) comprises a direct current step-down circuit (51) with isolation and a direct current step-up circuit (52) with isolation; the direct current voltage reduction circuit (51) and the direct current voltage boosting circuit (52) have the same circuit structure, and the direct current voltage boosting circuit (52) and the direct current voltage reduction circuit (51) are reversely connected in parallel; the input end of the direct current voltage reduction circuit (51) is connected with the output end of the direct current boosting circuit (52), and the output end of the direct current voltage reduction circuit (51) is connected with the input end of the direct current boosting circuit (52).
5. The high-reliability direct-current power supply for the substation according to claim 4, wherein the bidirectional DC/DC module (5) further comprises a diode D6, a diode D7, a latching switch S1 and an interlocking switch S2; the first end of the interlock switch S2 is connected with the positive bus of the direct current bus, the second end of the interlock switch S2 is connected with the first end of the latching switch S1, and the second end of the latching switch S2 is connected with the positive input end of the direct current step-down circuit (51); the negative input end of the direct current voltage reduction circuit (51) is connected with the negative bus of the direct current bus, the positive output end of the direct current voltage reduction circuit (51) is connected with the anode of the diode D6, the cathode of the diode D6 is connected with the positive end of the battery pack (4), and the negative output end of the direct current voltage reduction circuit (51) is connected with the negative end of the battery pack (4); the input end of the direct current boosting circuit (52) is connected with the battery pack (4), the positive output end of the direct current boosting circuit (52) is connected with the anode of the diode D7, the cathode of the diode D7 is connected with the second end of the interlock switch S2, and the negative output end of the direct current boosting circuit (52) is connected with the negative bus of the direct current bus.
6. The high-reliability direct-current power supply for the substation as claimed in claim 5, wherein said isolated direct-current step-down circuit (51) comprises a first controllable switch, a second controllable switch, a third controllable switch, a fourth controllable switch, a diode D1, a diode D2, a diode D3, a diode D4, an inductor L1, a capacitor C1 and a transformer T1; the first end of the second controllable switch is used as the positive input end of the direct current voltage reduction circuit (51), the second end of the second controllable switch is connected with the first end of the first controllable switch, and the second end of the first controllable switch is used as the negative input end of the direct current voltage reduction circuit (51); the first end of the fourth controllable switch is connected with the first end of the second controllable switch, the second end of the fourth controllable switch is connected with the first end of the third controllable switch, and the second end of the third controllable switch is connected with the second end of the first controllable switch; the cathode of the diode D1 is connected with the anode of the diode D2; the cathode of the diode D3 is connected with the anode of the diode D4; the anode of the diode D1 is connected with the anode of the diode D3, and the cathode of the diode D4 is connected with the cathode of the diode D2; the first input end of the primary side of the transformer T1 is connected with the second end of the second switching tube, the second input end of the primary side of the transformer T1 is connected with the second end of the fourth switching tube, the first output end of the secondary side of the transformer T1 is connected with the anode of the diode D2, and the second output end of the secondary side of the transformer T1 is connected with the anode of the diode D4; the first input end of the primary side of the transformer T1 and the first output end of the primary side of the transformer T1 are homonymous ends; the anode of the diode D3 is connected with the first end of the capacitor C1, the cathode of the diode D4 is connected with the first end of the inductor L1, and the second end of the inductor L1 is connected with the second end of the capacitor C1; a first end of the capacitor C1 is used as a negative output end of the direct current voltage reduction circuit (51), and a second end of the capacitor C1 is used as a positive output end of the direct current voltage reduction circuit (51).
7. The high-reliability direct-current power supply for the substation of claim 6, wherein the locking switch S1, the interlocking switch S2 and the controllable switch are all electromagnetic switches.
8. The high-reliability direct-current power supply for the substation of claim 6, wherein the latching switch S1 and the controllable switch are N-channel MOS transistors, first ends of the latching switch S1 and the controllable switch are drains of the MOS transistors, and second ends of the latching switch S1 and the controllable switch are sources of the MOS transistors.
9. A high reliability dc power supply for substations as claimed in claim 1, wherein each battery pack (4) comprises 18 batteries connected in series.
CN201922056772.8U 2019-11-25 2019-11-25 High-reliability direct-current power supply for transformer substation Active CN211556956U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113394765A (en) * 2021-06-11 2021-09-14 国网山东省电力公司莱芜供电公司 Parallel direct-current power supply system
CN114188932A (en) * 2021-10-25 2022-03-15 广西电网有限责任公司玉林供电局 Intelligent bus coupler applied to station direct-current power supply system
CN116742294A (en) * 2023-08-15 2023-09-12 江苏天合储能有限公司 Control method of battery cluster and energy storage system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113394765A (en) * 2021-06-11 2021-09-14 国网山东省电力公司莱芜供电公司 Parallel direct-current power supply system
CN114188932A (en) * 2021-10-25 2022-03-15 广西电网有限责任公司玉林供电局 Intelligent bus coupler applied to station direct-current power supply system
CN116742294A (en) * 2023-08-15 2023-09-12 江苏天合储能有限公司 Control method of battery cluster and energy storage system
CN116742294B (en) * 2023-08-15 2023-10-27 江苏天合储能有限公司 Control method of battery cluster and energy storage system

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