CN209434878U - Transforming plant distributed DC power system - Google Patents

Abstract

The utility model relates to a distributed DC power supply system of a substation, which belongs to the DC backup power supply system of a substation. The system includes multiple string battery units, and each string battery unit includes a backup battery pack, an active charging execution module, a passive discharge execution module, a string battery monitoring and maintenance module, and a string battery management unit. Among them, the string battery management unit is responsible for the data collection of single battery voltage, string battery voltage, string battery current, string battery temperature, and ambient temperature data, as well as the switching control of each working state of the distributed power supply. The utility model adopts the working mode of distributed arrangement of string battery capacity, realizes automatic battery balancing, full-capacity online automatic maintenance, and at least two sets of parallel connection of batteries, providing a safe electrical environment for battery cells, convenient access of string batteries, and backup The electrical function has strong redundancy and high reliability.

Description

Substation Distributed DC Power System

technical field

The invention belongs to a substation direct current backup power supply system, in particular to a substation distributed direct current power supply system.

Background technique

The DC backup power supply system is an important part of the substation system. It operates independently without being affected by the generator, plant power consumption and operation mode. In the case of external AC power failure, it provides protection and monitoring for some important loads. The device and telecontrol communication device provide uninterrupted DC power supply and provide lighting power for the accident scene.

With the improvement of the intelligence, digitalization and automation level of the substation DC system, higher requirements are put forward for the performance, safety and maintenance-free performance of the substation DC system. During nuclear capacity, only half-power nuclear capacity can be carried out. After 3 to 5 years, the barrel short-board effect of the battery pack will become more and more obvious, which will cause great uncertainty in the daily operation of the substation, and the battery pack will need to be replaced again.

Contents of the invention

In order to solve the above problems, the present invention provides a substation distributed DC power supply system, which is used to solve the problems of difficult maintenance of battery packs and short safe service time of the current substation DC power supply system.

In order to achieve the above objectives, the present invention provides a distributed DC power supply system in a substation, including a backup power mode formed by parallel connection of at least two string battery units, and various modules of the string battery units are connected in parallel in the substation according to the status of the busbar and the string battery On the DC system bus, the string battery unit includes a string battery switch, a backup battery pack, an active charging execution module, a passive discharge execution module, a string battery monitoring and maintenance module, a string battery management unit, and a passive discharge execution module One end connected in parallel with the active charging execution module is connected to the string battery switch, the other end connected in parallel with the passive discharge execution module and the active charging execution module is connected in series with the end connected in parallel with the string monitoring and maintenance module and the string battery, and the string monitoring and maintenance The other end of the module and battery string connected in parallel is grounded;

The battery string management unit is responsible for the voltage of the single battery, the voltage of the battery string, the current of the battery string, the temperature of the battery string, the switch state, the bus state, the ambient temperature data collection and the conversion control of each working state, each battery string The unit independently completes charging, discharging, floating charging, and maintenance operations through the string battery management unit. The string monitoring and maintenance module monitors the operating temperature of the battery pack, bus voltage, battery pack voltage, battery pack current, and battery cell voltage in real time. To ensure the stable and reliable operation of the distributed power system,

Preferably, the battery string switch can be a manual air switch or an electric control type operation switch.

Preferably, the backup battery pack is set according to the DC bus capacity requirement of the substation, and the battery strings can be lead-acid battery strings or lithium battery strings or a mixture of lead-acid battery strings and lithium battery strings.

Preferably, the active charging execution module includes a controlled charging switch and an anti-shock module. The active charging execution module can start charging through the controlled charging switch according to the state of the string battery pack, and prevent the voltage of the string battery from colliding with the busbar through the anti-shock module. Voltage mismatch.

Preferably, the passive charging execution module can automatically allocate the discharge time according to the power when the distributed power supply discharges to the bus, so as to ensure that each battery string is discharged in a balanced and orderly manner.

Preferably, the string battery monitoring and maintenance module includes a string battery maintenance module, a string battery information collection module, a single battery active balancing module, and a single battery information monitoring module. The daily maintenance and information collection functions of the entire battery pack.

Preferably, the string battery management unit performs reasonable state adjustment and control on the battery pack according to the battery state, and uploads and summarizes various states, actions, and alarm information of the string battery units through differential communication.

Preferably, the anti-shock module has an independent constant current function, so that the multi-string battery pack of the distributed power supply is always in a safe working state.

Beneficial effects of the present invention:

Various modules of the string battery unit are connected in parallel on the busbar of the DC system of the substation according to the status of the busbar and the string battery. Each string battery unit independently completes charging, discharging, floating charging, and maintenance operations through the The battery balancing module and monitoring module monitor the operating temperature of the battery pack, bus voltage, battery pack voltage, battery pack current, and battery cell voltage in real time to ensure the stable and reliable operation of the distributed power supply system.

By adding a balance system, it is guaranteed that each battery is always within the set safe working range during the working process, effectively avoiding the overcharge and overdischarge problems in the conventional battery system, and greatly delaying the time when the barrel effect of the string battery is obvious; Through the parallel operation of multiple strings of batteries, on the one hand, it effectively reduces the scope of influence of the barrel effect, avoids the power loss of the entire battery set due to the failure of one battery, and enhances the backup power capacity of the battery system of the substation; on the other hand, it ensures Under the premise of the backup power function, the multi-string battery system does not rely on external battery packs, and can realize full-capacity online maintenance through its own control, which is convenient for operation and maintenance; by adding PTC anti-shock components, it can In any case, the string battery is incorporated, which enhances the access applicability and backup capacity of the system string battery.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used to explain the present invention together with the implementation of the present invention, and do not constitute a limitation to the present invention.

Fig. 1 is a schematic diagram of the transition of the system working state provided by the present invention;

Fig. 2 is a schematic diagram of the charging operation state provided by the implementation of the present invention;

Fig. 3 is a schematic diagram of the floating charging operation state provided by the present invention;

Fig. 4 is a schematic diagram of the maintenance operation state provided by the implementation of the present invention;

Fig. 5 is a schematic diagram of the discharge operation state provided by the present invention;

Fig. 6 is a schematic connection diagram of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail in conjunction with the accompanying drawings and the implementation of a distributed power supply system using lead-acid batteries as backup power sources; it should be understood that The specific examples described are only used to explain the present invention, not to limit the present invention. Other systems, methods and or features of this embodiment will become apparent to those skilled in the art after reviewing the following detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims.

Example 1:

A substation distributed DC power supply system described in this embodiment includes a backup power mode in which at least two battery strings are connected in parallel, and various modules of the battery strings are connected in parallel to the DC system bus of the substation according to the status of the bus and the battery strings Above, the string battery unit includes a string battery switch, a backup battery pack, an active charging execution module, a passive discharge execution module, a string battery monitoring and maintenance module, and a string battery management unit. Operation switch, one end of the parallel connection of the passive discharge execution module and the active charging execution module is connected to the battery string switch, and the other end of the parallel connection of the passive discharge execution module and the active charging execution module is connected with the string monitoring and maintenance module and the string battery One end is connected in series, and the other end is grounded after the string monitoring and maintenance module and battery strings are connected in parallel.

The battery string management unit is responsible for the voltage of the single battery, the voltage of the battery string, the current of the battery string, the temperature of the battery string, the switch state, the bus state, the ambient temperature data collection, and the control of the conversion of each working state of the distributed power supply. The string battery unit independently completes charging, discharging, floating charging, and maintenance operations through the string battery management unit. , actions, and alarm information are uploaded and summarized through differential communication. The string battery monitoring and maintenance module includes a string battery maintenance module, a string battery information collection module, a single battery active balancing module, and a single battery information monitoring module. The battery pack voltage, battery pack current, and battery cell voltage are monitored in real time, and the string battery monitoring and maintenance module is responsible for implementing the daily maintenance and information collection functions of the entire battery pack to ensure the stable and reliable operation of the distributed power system.

Preferably, the backup battery pack is set according to the DC bus capacity requirement of the substation, and the battery strings may be lead-acid battery strings.

Preferably, the active charging execution module includes a controlled charging switch and an anti-shock module. The active charging execution module can start charging through the controlled charging switch according to the state of the string battery pack, and prevent the voltage of the string battery from colliding with the busbar through the anti-shock module. Voltage mismatch. The anti-shock module has an independent constant current function, so that the multi-string battery pack of the distributed power supply is always in a safe working state.

Preferably, the passive charging execution module can automatically allocate the discharge time according to the power when the distributed power supply discharges to the bus, so as to ensure that each battery string is discharged in a balanced and orderly manner.

As shown in Figure 1, in order to ensure that the distributed power system can complete tasks in various states, a complete system operation strategy has been formulated. The whole system completes various functions by configuring electric switches. The operating state and state transition are shown in the figure. When the substation bus is powered on, it includes three states: charging (power supplement + balance), floating charge, and maintenance. When the substation bus is de-energized, it includes one state of discharging. When the substation suddenly loses power, the system can transfer to discharge from any state when the bus voltage is online, and complete the backup function of the battery system.

String batteries are newly installed or replaced. There are more than two sets of battery strings in the system. When new installation or replacement is performed, the initial state of the battery pack is fully charged and there is a certain degree of self-discharge. The voltage of the battery pack is generally 2.25~2.35*n. In the disconnected state, connect the brand new battery pack to the distributed power supply, then close the switch of the string battery, maintain the voltage of the string battery at the bus voltage through the passive discharge module or active charging module, and accept the daily maintenance of the battery pack maintenance module. Management to maintain the best power storage status.

The charging state is shown in Figure 2. System charging includes two processes of power replenishment and balanced power replenishment, which are completed by the active charging module and the battery pack maintenance module respectively.

After the system performs the power backup function when the AC power is lost, it is necessary to recharge the battery strings. The battery string management unit connects the battery strings to the DC bus of the substation through the active charging execution module according to the current state of the battery strings. System, in this state, the battery pack voltage on the bus is the same, the anti-shock constant current module exits the working state, the bus voltage follows the string battery voltage, and the power replenishment process is completed. When the string battery voltage reaches the preset voltage or any single string battery reaches the preset voltage, the string battery management unit will switch the string battery to the active balanced charging state, so that each battery is in an independent balanced charging state until reach the preset voltage.

When the voltages of the string batteries on the bus are inconsistent, the string battery management unit enables the anti-shock constant current module, and the voltage or energy difference between the battery packs is consistent with the constant current through the anti-shock constant current module to complete the power supply process , and further transfer to the balanced power supply process through the balanced module.

The floating charging state is shown in Figure 3. After the charging process is completed, the state remains unchanged. Each battery in the string is floating charged at a fixed set voltage for a long time under the control of the string battery management unit, and the lead-acid battery is 2.25V. .

The maintenance state is shown in Figure 4. In order to ensure the power backup function, at least one battery string must be in the bus charging or floating charging state during the maintenance period. The maintenance process includes two processes: discharging core capacity and replenishing power. (1) Discharge core capacity, the core capacity string battery is connected to the maintenance load, the string battery management unit puts the corresponding string into the maintenance-discharge core capacity state according to the setting, and achieves the purpose of nuclear capacity through full capacity discharge according to the preset procedure. The string battery management unit records the voltage, current, time, and temperature information during the maintenance process for query. (2) Replenish electricity, the battery strings are connected to the maintenance charger, under the control of the battery string management unit, the corresponding battery strings enter the charging state, and the voltage of the battery pack is charged to the preset value through the charger, during which the strings are recorded. Battery and voltage, current and time information of each battery. After the charging is completed, the energy and voltage balance of the battery packs between the strings is completed through the charging anti-shock constant current module, and the battery packs of the strings further enter the balance and floating charging state to reach the normal battery backup state of the substation.

The discharge state is shown in Figure 5. When the substation loses power and the DC bus charging power supply is missing, the system immediately automatically supplies power to the 110V/220V DC bus through the passive discharge execution module, and then the string battery management unit adjusts the current status of each string Enter the discharge state to ensure that the distributed power system is only in the discharge state for supplying power to the bus.

To sum up, after reading the document of the present invention, those of ordinary skill in the art can make other corresponding conversion schemes according to the technical solutions and technical concepts of the present invention without creative mental work, all of which fall within the protection scope of the present invention.

Claims (8)

1. a kind of transforming plant distributed DC power system, which is characterized in that including by least two group string battery units in parallel Standby power mode, group string each generic module of battery unit are connected in parallel on transformer station direct current system bus according to bus and group string battery status On, described group of string battery unit includes that a group string cell switch, standby electric battery pack, active charge execution module, passive electric discharge execute Module, group string battery detection safeguard mould group and group string battery management unit, passive execution module and the active charge execution mould of discharging One end after block is in parallel is connect with group string cell switch, another after passively electric discharge execution module and active charge execution module are in parallel One end after one end is in parallel with group string monitoring and maintenance module and group string battery is connected, and group string monitoring and maintenance module and group string battery are simultaneously Other end ground connection after connection；

Described group of string battery management unit monomeric charge cell voltage, group string cell voltage, group string battery current, group string battery temperature Degree, switch state, bus state, ambient temperature data acquisition and each working condition conversion and control of distributed generation resource, each group of string Battery unit passes through group the string charging of battery management unit complete independently, electric discharge, floating charge, attended operation, group string monitoring and maintenance module The running temperature of battery pack, busbar voltage, battery voltage, battery pack current, battery cell voltage are monitored in real time, protected Demonstrate,prove distributed power supply system stabilization, reliability service.

2. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: group string cell switch It can be manual air switch or automatically controlled generic operation switch.

3. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: standby electricity battery pack root It is set according to transforming plant DC bus capacity requirement, group string battery can be plumbic acid group string battery or lithium group string battery or plumbic acid group string electricity Pond and lithium group string battery hybrid mode.

4. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: active charge executes Module includes controlled charging switch, protecting against shock module, and the active charge execution module can be according to a group state for string battery pack It is started to charge by controlled charging, prevents group string cell voltage and busbar voltage from mismatching by protecting against shock module.

5. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: passive charging executes Module can distribute automatically electric discharge duration when distributed generation resource is to bus discharge according to electricity, guarantee that each battery strings are balanced, have Sequence electric discharge.

6. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: group string battery detection Safeguard that mould group includes group string battery maintenance module, group string battery information acquisition module, single battery active equalization module, monomer electricity Pond information monitoring module, described group of string battery detection maintenance mould group are responsible for implementing to adopt the daily maintenance and information of entire battery pack Collect function.

7. a kind of transforming plant distributed DC power system according to claim 1, it is characterised in that: group string battery management Unit carries out reasonable status adjustment and control to battery pack according to battery status, by group every state of string battery unit, moves Make, warning information is uploaded by Differencing communication mode and summarized.

8. a kind of transforming plant distributed DC power system according to claim 4, which is characterized in that the protecting against shock mould Block has autonomous constant current function, is in distributed generation resource multiple groups string battery pack always under safe working condition.