A method for on-line load carrying capacity test of direct current battery pack of thermal power plant

Abstract

The present application belongs to the technical field of operation and maintenance of direct current storage battery group of thermal power plant, and discloses a kind of online load capacity test method of direct current storage battery group of thermal power plant, comprising the following steps: S1, carrying out preliminary inspection on the load capacity of direct current storage battery group; S2, selecting direct current security load on direct current 220V bus section as test object; S3, formulating temporary thermal configuration logic of direct current storage battery group combined with direct current security load; S4, executing safety isolation measures, checking the operation state of direct current security load and alternating current security load; S5, carrying out loading capacity verification on direct current storage battery group, collecting output voltage and output current of direct current storage battery group; S6, charging the storage battery group and restoring original operation mode after the test is completed.The present application solves the problem of online load capacity verification of direct current storage battery group, ensures that direct current power supply can be normally and timely put into when power supply of plant power security section is lost, and improves the reliability of equipment operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of operation and maintenance of direct-current storage battery group in thermal power plant, and particularly relates to a method for online load capacity test of direct-current storage battery group in thermal power plant. BACKGROUND

[0002] As the backup power supply of the direct-current system in power plant, the direct-current storage battery group provides uninterrupted power for relay protection, communication control, emergency lighting and the like. The power supply capacity is the last guarantee for the stable operation of plant and station equipment, and the performance directly relates to the safety and reliability of power system and communication system. Therefore, the stability and actual discharge capacity of the direct-current storage battery group are of great significance to the normal operation of power equipment. Under normal circumstances, the storage battery group is in a floating charge operation state. If the storage battery is not subjected to timely and large charge-discharge reaction for a long time, the service life of the storage battery group will be shortened due to accelerated aging. In order to ensure that the direct-current system power supply can be normally put into operation when the plant power supply fails, the first load capacity of the direct-current storage battery group must be matched with the actual first load capacity of the motor on the direct-current bus section. In the current domestic thermal power engineering design, the direct-current system security load mainly involves important auxiliary equipment such as generator direct-current sealing oil pump and turbine direct-current emergency oil pump. In order to avoid major equipment damage accidents such as bending of main shaft and wear of bearing bush, the important direct-current security load must be continuously powered during the whole plant power failure.

[0003] In engineering design, due to the lack of in-depth research on the characteristics and input time of the direct-current security load, and the lack of tracking and inspection of parameters such as voltage, internal resistance and capacity of the direct-current storage battery group in operation, the first load capacity of the direct-current storage battery group may be insufficient. In a power plant, the problem of insufficient first load capacity of the security power supply occurred during the unit trial operation. At present, the capacity is generally determined by periodically charging and discharging the storage battery group. However, this method usually uses a pure resistance load to discharge the storage battery group at a constant current, which cannot well reflect the capacity characteristics of the whole storage battery group actually loaded with inductive load such as direct-current motor. Therefore, how to determine the online load capacity of the direct-current storage battery group has become a problem that needs to be solved in thermal power plants. There is still a lack of effective solutions to the matching problem between the online first load capacity of the direct-current storage battery group and the actual first load capacity of the motor on the direct-current bus section. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for online load capacity test of direct-current storage battery group in thermal power plant, which solves the problems that the online load capacity of the direct-current storage battery group cannot be well determined by using a pure resistance load in the prior art, and the matching problem between the online first load capacity of the direct-current storage battery group and the actual first load capacity of the motor on the direct-current bus section cannot be solved.

[0005] In order to achieve the above object, the present application adopts the following technical scheme to achieve the above object: a kind of thermal power plant direct current battery pack online load capacity test method, comprising the following steps:

[0006] Step S1, the pre-examination of direct current battery pack load capacity is carried out;

[0007] Step S2, select the direct current security load on the direct current 220V bus section as test object;

[0008] Step S3, temporary direct current battery pack interlocking start-up of direct current security load thermal configuration logic is formulated;

[0009] Step S4, execute safety isolation measures, and check the operating state of direct current security load and alternating current security load;

[0010] Step S5, first loading capacity verification is carried out to direct current battery pack, meets the temporary direct current battery pack interlocking start-up of direct current security load thermal configuration logic of step S3, and the output voltage and output current of direct current battery pack are collected into step S6, otherwise return to step S2 and reduce the capacity of direct current security load;

[0011] Step S6, test end charging and restoring original operating mode to battery pack.

[0012] Preferably, the step S2 direct current security load is generator hydrogen side direct current sealed oil pump, generator air side direct current sealed oil pump, feed water pump turbine direct current emergency oil pump and turbine body direct current emergency oil pump.

[0013] Preferably, the step S3 includes the following steps:

[0014] Step S31, cut off the power supply of plant security section bus;

[0015] Step S32, temporarily exit the interlock start-up logic of emergency security generator and direct current security load, and the logic of temporary direct current battery pack interlocking start-up of direct current security load is formed.

[0016] Preferably, the step S4 includes that direct current security load disconnection manual operation is switched to control system operation, charger is disconnected with direct current battery, direct current battery and direct current 220V bus section are connected, direct current security load is in hot standby state, and alternating current security load is in operating state at the same time.

[0017] Preferably, the step S5 executes the thermal configuration logic of the temporary DC battery set associated with the DC security load of the step S3, the power supply of the auxiliary power security section is lost, the AC security load on the auxiliary power security section bus is tripped, when the power supply loss signal of the auxiliary power security section changes from "1" to "0", the logic of the temporary DC battery set associated with the DC security load is triggered after 1S delay, the output voltage and output current of the DC battery set are collected into the step S6, otherwise, the step S2 is returned to reduce the capacity of the DC security load, and the change of the output voltage of the DC battery set is simulated when the DC security load is loaded online.

[0018] Preferably, the output voltage and output current of the DC battery set in the step S5 are detected by using a WFLC-VI type portable electric quantity analyzer.

[0019] Preferably, the step S6 comprises the following steps:

[0020] The step S61 is to end the test and stop the operation of the DC security load.

[0021] The step S62 is to exit the thermal configuration logic of the temporary DC battery set associated with the DC security load, disconnect the DC battery and the DC 220V bus section, and connect the charger and the DC battery to charge the DC battery.

[0022] The step S63 is to restore the original operation mode after the charging is completed.

[0023] Preferably, the step S63 is to connect the charger, the DC battery set and the DC 220V bus section in parallel.

[0024] Preferably, the operation time of the DC security load in the step S5 is 15-20 min.

[0025] Preferably, the DC battery set is composed of 104 batteries, and the capacity specification of a single battery is 2V / 1600Ah.

[0026] Compared with the prior art, the method has the following beneficial effects: the method for the online load capacity test of the DC battery set of the thermal power plant is disclosed, the early inspection of the DC battery set with the load capacity ensures the next step of the test, the thermal configuration logic of the temporary DC battery set associated with the DC security load is formulated to make the DC battery set only supply power to the DC security load and execute the safety measures, the change scene of the terminal voltage of the DC battery set when the DC security load is successfully associated is simulated, and then the problem that the traditional pure resistance load is used to discharge the battery set with constant current and cannot well reflect the capacity characteristics of the actual load of the whole battery set, such as the inductive load of the DC motor, is solved, and effective technical guidance is provided for the online load capacity of the DC battery set.

[0027] Further, a temporary DC battery set joint start DC security load thermal configuration logic is formulated, when the power supply loss voltage signal of the station service security section changes from "1" to "0", a temporary DC battery set joint start DC security load logic is triggered after 1S delay, otherwise, return to step S2 to reduce the capacity of the DC security load, which can measure the capacity of the DC battery set with different service life.

[0028] Further, the online load capacity of the DC battery set is determined by the time of the DC security load operation, and the service life of the DC battery set is detected, so that the matching problem of the capacity of the DC battery set and the capacity of the motor loaded on the DC bus section is solved. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a flow chart of an online load capacity test method of a DC battery set of a thermal power plant.

[0030] Figure 2 It is a system diagram of a DC bus section of a thermal power plant.

[0031] Figure 3 It is a trend chart of the DC battery set terminal voltage of the DC security load when the DC motor is simultaneously loaded. DETAILED DESCRIPTION

[0032] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0033] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] An online load capacity test method of a DC battery set of a thermal power plant, as shown in Figure 1 the figure, comprises the following steps:

[0035] Step S1, pre-checking the DC battery bank load capacity;

[0036] Step S2, selecting the DC security load on the DC 220V bus section as the test object;

[0037] Step S3, formulating the temporary thermal configuration logic of the DC security load started by the DC battery bank;

[0038] Step S4, performing the safety isolation measures, and checking the operation state of the DC security load and the AC security load;

[0039] Step S5, performing the first loading capacity verification of the DC battery bank, satisfying the temporary thermal configuration logic of the DC security load started by the DC battery bank in Step S3, collecting the output voltage and output current of the DC battery bank into Step S6, otherwise returning to Step S2 to reduce the capacity of the DC security load;

[0040] Step S6, ending the test, charging the battery bank and restoring the original operation mode.

[0041] Before the operations of Steps S1, S2, S3, S4, S5 and S6, first check and confirm the state of each system and test object, and ensure that there is no maintenance operation on the involved systems and devices on site, which specifically includes:

[0042] (1) The on-duty operator confirms that the main engine lubricating oil system and the sealing oil system have been started, the generator hydrogen side AC sealing oil pump, the generator air side AC sealing oil pump, the feed water pump turbine AC emergency oil pump and the turbine body AC emergency oil pump are in normal operation state, and the DC system and the battery bank are in normal operation state.

[0043] (2) The on-duty operator confirms that the generator hydrogen side DC sealing oil pump has the starting condition, and the generator hydrogen side DC sealing oil pump motor is in hot standby state.

[0044] (3) The on-duty operator confirms that the generator air side DC sealing oil pump has the starting condition, and the generator air side DC sealing oil pump motor is in hot standby state.

[0045] (4) The on-duty operator confirms that the feed water pump turbine DC emergency oil pump has the starting condition, and the feed water pump turbine DC emergency oil pump motor is in hot standby state.

[0046] (5) The on-duty operator confirms that the turbine body DC emergency oil pump has the starting condition, and the turbine body DC emergency oil pump motor is in hot standby state.

[0047] (6) The rated power of each DC security load is shown in Table 1.

[0048] Table 1 each DC security load rated power

[0049] Serial No. Name Rated Power (kW) 1 Generator hydrogen side DC seal oil pump 5.5 2 Generator air side DC seal oil pump 22 3 Feed water pump turbine DC emergency oil pump 10 4 Turbine body DC emergency oil pump 30 Total 67.5

[0050] The specific operation steps of steps S1, S2, S3, S4, S5 and S6 are as follows:

[0051] (1) The security measures and technical measures are prepared by the relay protection personnel, the above measures, the relevant instruction manual and the operation guide are organized to be learned, the dangerous points of operation are familiarized, the drawings and data required for operation are prepared, and the running status of the battery pack is understood.

[0052] (2) The on-duty operator checks and confirms that there is no damage to the appearance of the battery body, no short circuit, local heating, sulfuration, bending and fracture of the plate, no moisture and dust on the battery shell, and the name and identification of each group of batteries are accurate and clear. At the same time, the connection plate between the batteries and the power cable are checked and confirmed to be firmly pressed.

[0053] (3) The value long contacts the thermal worker to modify the logic connection start condition of the emergency security diesel generator of the unit: exit the diesel generator interlocking input logic.

[0054] (4) The value long contacts the thermal worker to form a temporary logic of starting the hydrogen side DC sealing oil pump of the generator, the air side DC sealing oil pump of the generator, the turbine DC accident oil pump of the feed water pump and the turbine body DC accident oil pump. When the power supply loss voltage signal of the station power security section changes from “1” to “0”, the falling edge is used to trigger the starting instruction of the above-mentioned DC security load after 1s delay.

[0055] (5) The on-duty operator sets “forbidden operation” on the DCS interlocking input operation interface of the diesel generator, and places the remote / local conversion handle on the diesel generator local control cabinet in the “forbidden” position.

[0056] (6) The value long contacts the relay protection personnel to remove the remote closing instruction cable in the diesel generator local control cabinet, and to make good line number marking and insulation wrapping.

[0057] (7) The on-duty operator switches the “remote / local” position switch of the generator hydrogen side DC sealing oil pump local control cabinet to the “remote” position.

[0058] (8) The on-duty operator switches the “remote / local” position switch of the generator air side DC sealing oil pump local control cabinet to the “remote” position.

[0059] (9) The on-duty operator switches the “remote / local” position switch of the feed water pump turbine DC accident oil pump local control cabinet to the “remote” position.

[0060] (10) The operator on duty switches the “remote / local” position switch of the local control cabinet of the DC emergency oil pump of the turbine body to the “remote” position.

[0061] (11) The operator on duty turns on the power circuit breakers of the generator hydrogen side DC sealing oil pump, the generator air side DC sealing oil pump, the feedwater pump turbine DC emergency oil pump and the turbine body DC emergency oil pump on the unit's 220V DC system feeder panel.

[0062] (12) The operator on duty sets the battery input line and busbar connection switch to the "battery output to busbar" position, and at the same time sets the charger output switch to the "off" position, so that the charger stops running and the battery pack supplies power to the DC 220V busbar alone. Figure 2 shown.

[0063] (13) The on-duty operator remotely disconnects the incoming switch of the power supply of the plant power safety section busbar, and switches the incoming switch from operation to hot standby state. At this time, the power supply of the plant power safety section busbar loses voltage, and the AC safety load on the busbar loses power and trips. At the same time, the DCS pressure loss signal changes from "1" to "0" and the condition is met. After a delay of 1s, a long pulse command is issued to start the generator hydrogen side DC sealing oil pump, the generator air side DC sealing oil pump, the feed water pump turbine DC emergency oil pump and the turbine body DC emergency oil pump, thereby simulating the change of terminal voltage when the DC battery group is online and loaded with the selected DC safety load at the same time.

[0064] (14) The on-duty operators and relay personnel shall pay close attention to the operating status of the DC safety load and the changes in the terminal voltage of the DC battery group in real time, use the WFLC-VI portable power analyzer to record the waveform, and make records of the relevant parameters. Figure 3 .

[0065] (15) From Figure 3 It can be seen that during the DCS interlocked start-up of the four DC oil pumps, all oil systems operated normally, and the DC battery pack showed no abnormalities. During the startup process, the DC battery pack output current was 254A, and the terminal voltage was 213V. After 15 minutes of online load supply, the DC battery pack output current was 210A, and the terminal voltage dropped to 208V, meeting the capacity requirements for emergency start-up of the DC safety load in the event of a sudden power outage in the auxiliary power safety section busbar.

[0066] (16) After the test, the on-duty operator stopped the operation of the four DC oil pumps according to the situation. At the same time, the shift leader contacted the thermal engineer to restore the temporarily formulated thermal configuration logic. The operator took measures to charge the battery pack, set the battery input line and busbar connection switch to the "battery exit" position, and set the charger output switch to the "charger output to battery" position.

[0067] (17) The shift supervisor contacted the relay protection personnel to set the DC system 220V battery pack to equalize charge control settings, using a 160A current for constant current charging. When the battery pack terminal voltage rises to the 244.4V voltage limit, it automatically switches to constant voltage charging. After the DC battery pack switches to float charge, the relay protection personnel measures the voltage and internal resistance of each single battery, as well as the terminal voltage of the battery pack, and records the relevant data.

[0068] (18) After charging is completed, the operator on duty will set the charger output switch to the "charger output to bus" position to restore the normal power supply of the 220V DC bus. Set the battery input and bus connection switch to the "battery output to bus" position to restore the original operation mode of the DC system.

[0069] It's important to note that this test involved direct online battery capacity testing. Due to the large variations in discharge current, a shorter discharge time was used to prevent damage to the battery pack due to prolonged discharge. Generally, according to the DL / T724-2000 Technical Specification for Operation and Maintenance of Battery DC Power Supply Devices for Power Systems, discharge should be conducted at a constant current of 160A. Discharge should be stopped when the battery pack voltage drops to 187.2V or the individual cell voltage drops to 1.8V. A constant current-constant voltage-float charge cycle should be repeated two or three times. If the battery pack capacity does not reach more than 80% of the rated capacity after three full-capacity verification cycles, the battery pack is considered to have reached the end of its service life. In this test, the DC battery pack operated directly with a motor load. Since the discharge current cannot be controlled to a constant 160A, a standard discharge time is difficult to determine. It is recommended that the discharge time be based on the time it takes the operator to restore AC power (diesel generator power) after a plant power outage. A typical discharge time of 15-20 minutes is reasonable. In addition, the valve-regulated battery verification discharge cycle should be strictly tested in accordance with the DL / T724-2000 regulations: Newly installed valve-regulated battery packs should undergo a full verification discharge test, and then a verification test should be carried out every 2-3 years. Valve-regulated batteries that have been in operation for more than 6 years should be subjected to a verification discharge test once a year.

[0070] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for online load capacity testing of DC battery packs in thermal power plants, characterized in that: The following steps are involved: Step S1: Perform a preliminary inspection on the loaded capacity of the DC battery pack; Step S2: Select the DC safety load on the DC 220V bus segment as the test object; Step S3: Formulate a temporary thermal configuration logic for connecting the DC battery pack to the DC safety load; Step S4: Execute safety isolation measures and check the operating status of the DC safety load and the AC safety load; Specifically, the manual disconnection operation of the DC safety load is switched to the control system operation, the charger is disconnected from the DC battery, the DC battery is connected to the DC 220V bus segment, the DC safety load is in hot standby state, and the AC safety load is in operation; Step S5: Perform an initial load capacity check on the DC battery pack. If the thermal configuration logic for temporarily linking the DC battery pack to the DC safety load in step S3 is met, collect the output voltage and output current of the DC battery pack and proceed to step S6. Otherwise, return to step S2 to reduce the capacity of the DC safety load. Step S6: After the test is completed, the battery pack is charged and the original operation mode is restored.

2. The method for online load capacity testing of a DC battery pack in a thermal power plant according to claim 1, characterized in that: The DC safety loads in step S2 are the DC sealing oil pump on the hydrogen side of the generator, the DC sealing oil pump on the air side of the generator, the DC emergency oil pump of the feedwater pump turbine and the DC emergency oil pump of the turbine body.

3. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 1, characterized in that: The step S3 comprises the following steps: Step S31, cutting off the power supply of the auxiliary power safety section busbar; Step S32: Temporarily exit the interlocking start logic of the emergency safety generator and the DC safety load, and establish a temporary logic of starting the DC safety load with the DC battery group.

4. The method for online load capacity testing of a DC battery pack in a thermal power plant according to claim 1, characterized in that: Step S5 executes the thermal configuration logic of temporarily activating the DC safety load in conjunction with the DC battery pack in step S3. If the auxiliary power safety section busbar loses power, the AC safety load on the auxiliary power safety section busbar trips. When the auxiliary power safety section power loss signal changes from "1" to "0," a one-second delay triggers the logic for temporarily activating the DC battery pack in conjunction with the DC safety load. The output voltage and current of the DC battery pack are collected, and the process proceeds to step S6. Otherwise, the process returns to step S2 to reduce the capacity of the DC safety load, simulating the change in output voltage when the DC battery pack is online and simultaneously loaded with the DC safety load.

5. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 1, characterized in that: In step S5, the output terminal voltage and output current of the DC battery pack are detected using a WFLC-VI portable power analyzer.

6. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 1, characterized in that: The step S6 comprises the following steps: Step S61: The test ends and the DC safety load stops running; Step S62: Exit the temporary thermal configuration logic of the DC battery group and start the DC safety load, disconnect the DC battery and the DC 220V bus segment, and connect the charger to the DC battery to charge the DC battery; Step S63: Charging is completed and the original operation mode is restored.

7. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 6, characterized in that: The step S63 is to connect the charger, the DC battery pack and the DC 220V bus segment in parallel.

8. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 1, characterized in that: The operation time of the DC safety load in step S5 is 15-20 minutes.

9. The method for online load capacity testing of DC battery packs in thermal power plants according to claim 1, characterized in that: The DC battery pack consists of 104 batteries, and the capacity specification of a single battery is 2V / 1600Ah.

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