1. The operation and maintenance rules of the DC power supply system for the station shall carry out a full verification discharge test for the newly installed VRLA battery pack, and a verification discharge test shall be carried out every two years thereafter.
For batteries that have been in operation for more than four years, a verification discharge test is required once a year.
At least 1 time per month the voltage measurement of the single battery, at least 1 time per year of the battery internal resistance test.
Battery internal resistance test, check dischargeIt is one of the effective ways to test the performance of the battery.
2. Problems in the operation and maintenance processVoltage measurements are performed manually and are inefficient
The battery status monitoring function of the traditional power supply system is not comprehensive, the voltage monitoring accuracy is insufficient, and it cannot effectively reflect the real operating conditions of the battery, there is no report export function, and the operation and maintenance staff need to manually measure the voltage once a month.
The voltage measurement needs to be carried out by at least two people, and the voltage measurement of each group of batteries takes 20 minutes, and only 4-5 stations can be measured per day, which is cumbersome to sort out the measurement data.
The traditional DC power supply has no internal resistance test function, which requires operation and maintenance personnel to use mobile devices to manually measure, which is inefficient, has large data deviations, and may even cause short-circuit accidents
The internal resistance measurement needs to be carried out by at least two people, and each group of battery internal resistance measurement takes 30 minutes, and can only measure 2-3 stations per day.
The measurement of internal resistance requires careful operation by professionals, and the contact force between the measuring pen and the battery and the measurement position will lead to a large deviation in the measurement results, and the incorrect gear may also cause the equipment to burn out and the battery to short circuit.
3) The traditional power supply system does not have an effective battery nuclear capacity maintenance function, and needs to rely on the manual verification of mobile maintenance equipment, with many wiring, large number of equipment, large weight, and complex operation, which is easy to cause short circuit, electric shock or equipment burning accident, and the risk is large
The on-site preparation of the mobile maintenance equipment takes about 1 hour, and after the wiring is completed, the on-site wiring is messy, which brings potential safety hazards to the inspection work, and the maintenance equipment needs to be dismantled again to restore the site after up to 10 hours of manual verification.
3. Eighteen countermeasures for half-capacity automatic check and discharge: When the DC power supply system for the station is running, it is forbidden for the battery pack to be separated from the DC bus. The DC power supply system of 110kV and below voltage level substation is mainly configured with single electricity and single charge, and there are two automatic verification methods:
Semi-nuclear capacity: the battery is not separated from the bus when the nuclear capacity, and 50 of the rated capacity is discharged with i10 current constant current. When discharging, the terminal voltage of the battery pack shall not be less than 2V N. There are two methods of half-core capacitance, one is the direct discharge load method by adding diode + charging switch; The other is to reduce the voltage of the charger and combine it with normal load + discharge load. The second method has control risks due to the need to control the charger, and there are multiple manufacturers of field equipment at the same time, and each agreement is not public, which is difficult to apply in batches.
Full capacity: If there is a spare battery pack, the backup battery can be connected to the DC system, and the full capacity of the battery pack that is out of the system can be checked with i10 current. Although the use of backup battery pack can be checked at full capacity, the construction cost is high, the wiring is complex, and the backup battery usually needs maintenance and management, which is not suitable for batch application.
**Nuclear capacity: The battery pack does not need to be separated from the system, which is safe, convenient and fast
In the half-core capacity mode, the charging switch needs to be connected in series in the battery circuit, and the rectifier diode is connected in parallel at both ends of the charging switch, and the discharge switch is added on the battery side of the charging switch. There is a software and hardware logic lock between the charge and discharge switches.
Before discharging, the internal resistance of the battery is tested through the monitoring device, the voltage internal resistance data is derived, and then the battery charging switch is disconnected, the discharge switch is closed, the discharge parameters are set to start discharge, and the voltage and current data are automatically recorded.
If the AC is interrupted during the discharge process, the battery can supply power to the bus through the diode to ensure the continuous power supply of the DC bus, and the system will automatically stop discharging.
Multiple protection measures:
Monitor the status of the DC system before discharge, operate the two-person countersigning mechanism, switch software and hardware interlock, sequence control, switch remote control pre-selection, execution, anti-calibration, discharge load overvoltage and overcurrent self-protection, communication interruption protection, and overtemperature protection.
During the discharge process, the battery pack will be automatically stopped when the battery is depressed, the cell voltage is low, and the discharge capacity or discharge time is reached. After the discharge is completed, the discharge report is exported, and the intelligent nuclear capacity system supports automatic or manual recovery of the DC power supply system to the normal operating state.
4. Full-capacity automatic check and discharge: 220kV and above voltage level substation DC power supply system, double charge or double charge triple charge mode. When the insulation of the two sections of the bus is normal and the voltage difference does not exceed 2%, the bus tie switch can be closed, and one of the battery packs can be checked with the full capacity of I10 current, when the terminal voltage of the battery pack drops to 1When 8V N, stop discharging to judge whether the battery capacity meets the requirements of the regulations.
At present, there are two ways of intelligent nuclear capacitance system, the first is the one-key discharge mode, which requires the addition of remote-controllable mother-to-investment bus tie switch and charge-discharge switch in the system, perfect power monitoring equipment, and software and hardware logic locking and sequence control to achieve one-key nuclear capacitance discharge; The second mode is semi-automatic, only the battery discharge switch is added, and the DC system is manually operated to the discharge state before discharge, and the discharge switch is closed, and the discharge is operated.
One-click operation:
Test the internal resistance of the battery before discharge, derive the voltage internal resistance data of the battery, judge that the insulation of the two sections of the bus is normal and the voltage difference is not more than 2%, close the bus tie switch, disconnect the bus switch, disconnect the charging switch, close the discharge switch, set the discharge parameters, start the discharge, and automatically record the voltage and current data.
Multiple protection measures:
Monitor the status of the DC system before discharge, operate the two-person countersigning mechanism, switch software and hardware interlock, sequence control, switch remote control pre-selection, execution, anti-calibration, discharge load overvoltage, overcurrent self-protection, AC power-off protection, communication interruption protection, and overtemperature protection.
During the discharge process, the battery pack will automatically stop discharging when the voltage is low, the cell voltage is low, and the discharge capacity or discharge duration is reached. After the discharge is completed, the discharge report is exported, and the intelligent nuclear capacity system supports automatic one-click recovery or manual recovery of the DC power supply system to the normal operating state.
5. Nuclear capacitance discharge remote networkingWuhan Halma Power complies with the regulations and specifications of the power industry, extensively collects the operation experience and opinions of the DC system for the station, and works closely with the on-site operation and maintenance personnel to conduct in-depth research and development of the MDC-1000G battery pack multi-functional condition monitoring and voltage loss compensation system. Provide a set of multi-functional, modular comprehensive monitoring solutions with multi-state monitoring, open-circuit monitoring, voltage loss compensation, fault recording and automatic charging and discharging for substation battery packs.
Diagram of the system composition.
MDC-1000G battery pack multi-function condition monitoring and voltage loss compensation system.
The system has a remote monitoring function, and the station-side equipment information is uploaded to the intelligent monitoring and management master station through the power 2m network or integrated data network, and the station-side information or control station-side equipment can be viewed at the master station. The system perfectly solves the common and difficult to solve the pain points of the current battery pack, and provides a good guarantee for the reliable operation of the battery pack and the DC system.