Battery fault preset application of substation

　　Author ：Iflowpower – Portable Power Station Supplier

First, introducing the highly developed society with high power system and computer network, in order to prevent the service interruption of the power abnormality, except for the reliability of the power supply system, use the battery to supply uninterruptible power supply in many occasions, prevent accidental power outages Bringing the impact, a large number of batteries in the DC power supply system within the power system. The use of the largest battery in the power system is a valve-controlled lead-acid battery (VRLAB below), which is also the most widely used battery. VRLAB uses a cathode absorption technology, so it does not require water maintenance in operation, and Vrlab is called a maintenance-free battery in the early stage of the market, and the service life can reach 10-15 years.

The emergence of VRLAB has brought a revolution to the entire battery industry, which triggers a huge demand for VRLA batteries in all industries, particularly electricity and communication industries. After more than ten years of VRLAB's large number of applications, VRLAB revealed some shortcomings, and its service life did not meet people's expectations. The relevant information indicates that Vrlab is in use for 3 -4 years, and a large part of the battery pack is difficult to detect by capacity, a few more than 6 years.

In actual use, only a few users can truly have conditions to periodically check the battery and test the battery, in many cases, it is found that the battery damage or discharge capacity does not decrease the design requirements after the market is powered off. Lose huge loss. Haikou Haikou Power Supply Bureau has a variable substation of various VRLABs more than 20,000 sections.

During the actual use, many batteries cannot be discharged through the verification capacity after 4-5 years. In order to improve the power of the Haikou Power Supply Bureau to maintain the capacity of the battery, effectively extend the service life of the battery. The Haikou Power Supply Bureau used 220KV substations in January 2009, the DLT_B8500 battery fault preset developed by Dingrt, helping maintenance personnel master the performance of the battery and replace the backward battery in time.

Second, the measurement principle Measure the valve control lead-acid battery end voltage cannot reflect the actual capacity characteristics of the battery, and can immediately determine the battery or the battery of the connection problem by measuring the internal resistance, and give a alarm information. Impedance analysis is a common method in electrochemical research, and is the necessary means of battery performance research and product design. The VRLAB used in the spare occasion is very large.

When dozens to thousands of security, the internal resistance value of the battery is small, with the increase in battery capacity, the internal resistance is small, such as a battery of 3000AH, and the internal resistance value is generally 30-50 micro European. Due to the low resistance, the battery positive and negative electrode outputs DC voltage, and it is necessary to accurately measure the internal resistance, especially when the online measurement is measured, the battery end is dynamically changed during the battery end. The measurement of an alternating spectrum method is effective to solve the problem that the measurement caused by the charging machine ripple and load changes.

When using a controlled current,δI = iMaxSin (2πFT), the voltage response appears is:δV = vmaxsin (2πFT +φ) If the controlled voltage is used,δV = vmaxsin (2πFT), the current response is:δI = vmaxsin (2πFT-φThe impedance of the two situations is: that is, the impedance is related to the frequency-related complex impedance, the mold | Z | = Vmax / IMAX, the phase angle isφ. In theory, the battery is fed into a AC current signal, and the voltage change from this signal can be measured to measure the internal resistance of the battery. R = VAV / IAV VAV --- is the average value of the AC signal; Iav ---- is in actual use, due to the limited amplitude of the feed signal, battery The internal resistance is in the micro-European or millio-class, so the magnitude of the voltage change is also in the micro-European grade, and the signal is easily interfered.

In particular, when online measurement, the impact is more affected, and the internal resistance measurement technique and synchronous detection method based on digital filter can partially overcome external interference, obtain a relatively stable internal resistance data. The synchronous detection method circuit structure is simple, as shown in Figure -1, the phase triggered by the clock, synchronous excitation signal and the phase of the detection circuit. From the measurement accuracy and measurement method, this method can not only accurately measure the ohmic resistance of the battery, but also measure the polarization resistance of the battery, the objective reaction of the battery's capacity and life, is internationally recognized.

Methods. The device consists of a control unit, a detection module, an internal resistance module, a related software, and auxiliary components, and a control unit can access multiple detection modules to complete monitoring management of battery packs of different only and different voltage specifications. Device schematic diagram as shown in Figure 2: Control unit, used for data transmission, processing, and human-machine interface operation, with remote (centralized) management RS-485 (RS-232) interface, detection module control port, operation keyboard, Chinese Or English, different from specifications) display panel, sound and light alarm and alarm output contact.

The control unit displays battery data in real time, intelligent analysis data, timely alarms for abnormal battery operation. Through the bus structure control detection module, the data acquired by the detection module is collected, and the unit is judged to the occurrence of the incident, and the sound and light alarm, the signal, storage, and query functions of the data are issued, which for operators for field event processing. Detection unit, complete data acquisition, and transmit data to control module.

High-precision, high-efficiency data acquisition module adopts modular design methods, which takes into account the principle of dedication and generalization, flexibility, according to the needs of sampling point, and each module can be used separately, and can also be freely combined. Monitoring occasion. Internal resistance unit, in the case where internal resistance detection is to be used, the internal resistance module is used in conjunction with the detection module.

The internal resistance module is adapted to the distributed structure of the system, and accepts the scheduling of the detection module. It issues an excitation signal for the battery pack. Due to the use of special technologies, there is no adverse effect on online operation.

IV. Execution Method This application selects 2 sets of battery packs of Yongzhuang 220KV substation subordinates from Haikou Power Supply Bureau, each battery nominal voltage is 2V, nominal capacity is 300ah. 108 batteries per combination.

Each two sets of batteries are applied with a control unit, each set of batteries applied three detection units and an internal resistance unit. Since the number of batteries that each detection unit can be collected can be up to 36 sections, three detection units are configured. In the maintenance office, a server is placed.

The server is equipped with a background data sampling service program. As long as the server is turned on, it is possible to real time to remotely collect the data that is installed on the site's DLT_B8500 battery life and fault preset to the server, the server will put the data from each remote transmission. In the overbet database, call to view when maintaining post-maintenance.

At the same time, the front desk is also installed in the server, and the operation of the main screen, graphics data, etc. can be displayed in real time to complete the monitoring of the battery. You can view the running parameters and performance parameters of the battery pack in real time, and there is an exception to display the alarm type of the battery in real time.

In addition, there is also a battery performance and test data analysis function, and intuitively understand the performance of the battery performance, which is easy to better predict the changes in the battery. The discharge data analysis function has data recording functions such as voltage of the battery discharge process, forms the discharge curve of each battery, and utilizes the discharge curve to more accurately analyze the performance of the battery. You can understand the various parameter indicators of the battery in time without the site.

5. On-site tests have been collected by various parameter data for substation battery, we can master the performance of the battery in real time. From Fig.

3 and Fig. 4, the floating voltage consistency of the two sets of battery pack monomer batteries is better. The battery is in different states, and its internal resistance is also different.

Figure 5 is a 1 # battery pack as a test object, the value of the value is measured in the floating state, stopping the floating charge, and the battery internal resistance is small after transfer. The variation is uniform, with an average of 6.5%, which can be interpreted as the effect of polarization internal resistance in the floating state.

Figure 6 is a voltage change and internal resistance curve when the 2 # battery pack is close to 10 hours. It can be seen from the data of Fig. 6.

After the battery enters the discharge state, the internal resistance is lowered by the value of the floating state to a stable value. This value is stable in the platform stage of the battery discharge, and after the discharge capacity reaches 80%, the internal resistance rises sharply. After transferring the charge, the internal resistance quickly returns to the normal value.

Different failure modes of the battery are reflected in the amplitude of the internal resistance change. To this end, two batteries that were only used in the original degradation and 1 new battery were compared, and Fig. 7 is a battery discharge curve in different deterioration modes.

Variable amplitude of different deterioration of battery internal resistance can be found by comparative testing. Arrange from the magnitude of the output capacity, sequentially, the battery, the battery, the battery is lost after water. Sixth, conclusions 1) The operation parameters of the battery are important to the control of the charger, especially the floating voltage of the battery, directly affecting the battery's floating service life.

The world's best battery is not working for a long time in a high (or low) floating charge. The measurement of the floating charge voltage is very high in accuracy requirements. Comprehensive analysis can detect events that exceed the battery parameter limit in the battery pack, including: the charging current is too large, the discharge current is too large, the battery pack floating voltage is high, the battery pack is low, the battery pack is over-discharge, single Battery floating charge voltage, single battery floating charge, single battery over-discharge.

Through technical transformation, the case where the battery performance attenuation caused by improper maintenance is prevented from maintenance. 2) Battery monitoring In addition to discovering abnormal operating conditions of the battery, the most important thing is to predict the failure of battery failure. Online measuring internal resistance of each single battery is an innovation point of modern battery detection technology, and the measurement accuracy is directly related to the accuracy of the analysis.

The change in internal resistance can be regarded as an indication of battery performance or change in capacity. Obvious internal resistance changes indicate that the battery has a large performance change, but this change may be related to the battery of different manufacturers. In response to the results of the experimental study, the company currently exceeds the average value of 20%, that is, incorporating the scale of the key inspection.

3) After comprehensively studying the operation characteristics of the battery, and has an effective monitoring of the battery pack, including the battery pack within the unit cell, further amendments to the existing DC battery operation management procedures are revised on the basis of the operating management procedures of the national electrical equipment. And implementation, it is a system guarantee that truly improves the safe and reliable operation of the grid DC system.