Since 2002, Shandong Z, J and other 500kV old substations have replaced the original fixed acid-proof batteries with valve-controlled lead-acid batteries, and station J has replaced two groups of American "Leopard" POWER series PRC-2450XCGFM-II batteries, 104 in each group. Nuclear capacity testing was carried out in late May 2005 according to the manufacturer's instructions.

Production at the end of 2002, 500, LC KVCQ stop using german-made RETARDANT sun (Germany), battery, respectively, in 2005 in July and August conducted a nuclear test, the results present situation is not ideal, found many unqualified battery, through the test, battery maintenance and the environment is not appropriate, Cause part of the battery life is far from the prescribed requirements, only in less than two years, 500kV substation has nearly 30 battery battery gate reaction (corrosion) accelerated, shortened life and scrap.

This situation is common in other places, for example, a company in Hebei once had two sets of valve-controlled lead-acid batteries, due to their own quality problems, in the summer due to hot weather, when many batteries bulging out of shape. The main factors that shorten life span are: Although the electric power system is already all use valve control type lead acid battery, battery compartment still follow the « electric power equipment in the typical fire regulations » acid in fixed against the flame-proof type lead-acid battery design, without considering the characteristic of valve control type of battery and the requirement of temperature, free maintenance is by no means do not maintain, but it is strict in field management, environment;

When the temperature is too high, the battery gate reflects faster and accelerates aging; The temperature is too low, the battery capacity is reduced, the floating charging voltage is high, also because the gate reflects faster, accelerating aging; At the same time, the floating charge is low, the battery works in the undercharge state, leading to the accumulation of lead sulfate, the battery capacity decreases, and the battery life is shortened. Therefore, this paper analyzes the maintenance of battery in substation to provide reference for prolonging the service life of battery.

The service life of the battery is closely related to the strict use method

Valve control type lead acid battery has many traditional GG type open type lead-acid batteries, GGF fixed acid flame-proof type lead-acid batteries do not have the advantage of, such as clean, simple installation, do not need to allocate the electrolyte, no hurt and explosion danger, sulfate does not need to be balanced charge, because of valve control type start-up pressure is 1.5 bar, As high as 99% water vapor recombination rate, effectively reduce the internal gas generation, operation and maintenance without hydrogen and oxygen precipitation, but at the same time, the requirements for environmental conditions are also more stringent.

Store daily battery checks

As with batteries, the charging system ensures that the charging device works properly. In order to make the battery can be in the standby state under full capacity, the battery is often used in parallel with the charger, connected to the DC bus, the charger in addition to the regular DC load, give the battery a proper charging current, to supplement the battery self-discharge, this way is called floating charge. If the charging unit breaks down, all the DC load is borne by the battery bank. After the fault is eliminated, the battery will be fully charged and the floating charging operation mode will be resumed.

Charging machine adopts shenzhen OTT ATC230 intelligent high frequency switch power supply module, the built-in CPU, coordination management module, the operations and protection in five modules meet the battery charging current (0.1 C10) combined with constant load current, the other by step-down components provide control output, and to accept the upper machine electrical isolation of digital communication way of control. It has the advantages of high intelligence, high efficiency and high reliability. 5 groups of parallel use, pay attention to the requirements of multi-machine parallel: current limiting gear should be in the same gear; The floating charging voltage and equalized charging voltage of each module must be consistent. Can directly display the output voltage, current and has input overvoltage, undervoltage, output overvoltage, overheating, short circuit and lightning protection, which any group of charging machine abnormal can exit the work for inspection and replacement, other groups will continue to work, does not affect the operation of the battery, less noise, easy maintenance.

At present, seven charging modules have been replaced at 500kVWF station, CQ station, LC station and BZ station from 2004 to 2006. The floating charging voltage displayed on the charger should be 235.5V(the factory parameter setting is 2.26V for each battery), and the control bus voltage should be set as 220V.

Monthly battery system inspection

Floating charging voltage of system:

The terminal voltage of the battery pack is measured and recorded online, and compared with the display value of the charger instrument. The error of 0.5% is required. The floating charging voltage of the battery has a great impact on its life and capacity. If the floating charging voltage is too high, the floating charging flow will rise, leading to the acceleration of the battery gate reaction (corrosion) and the shortening of the battery life. If the battery is undercharged, lead sulfate will accumulate, the battery capacity will decrease, and the battery life will be shortened. The floating charging mode always keeps the battery in full charge state, and the maximum voltage variation range of a single battery must be between 2.25 and 2.30V at 25°C. If the measurement result is different from the displayed value of the charger, the instrument of the charger needs to be calibrated.

Reduce the harm of high temperature to the battery:

The battery temperature should be measured at the same point every month, mainly to monitor the temperature in the battery room. When the battery temperature is higher than 25°C or lower than 20°C, and the temperature change exceeds 2.5°C, you need to adjust the system temperature. The manufacturer requires that the ambient temperature of the battery should be between 20°C and 25°C. High temperature has a great impact on the life of the battery. When the ambient temperature is higher than 25°C, the grid reaction (corrosion) of the battery will be accelerated, which will shorten the life of the battery.

The system temperature compensation floating charging voltage cannot fundamentally guarantee the battery life:

Intelligent high-frequency switch ATC230 power module has automatic temperature compensation function, which can make the battery current change due to temperature change by changing the floating charging voltage to adjust. However, only the auxiliary function, high temperature caused by the acceleration of battery gate reaction (corrosion) is one of the reasons for the shortening of battery life.

At the same time, we know that when the temperature is reduced to below 0°C, the floating charging temperature regulating voltage reaches more than 2.3V, which will seriously affect the service life of the battery. The battery environment reaches the monitor through the temperature transmitter. The measured temperature deviates from 20°C to 25°C and is sent out by the monitor when the temperature rises by 1°C ↓0.52V and when the temperature falls by 1°C ↑0.52V. But the temperature range is limited by the control voltage, so the system temperature compensation floating charging voltage does not play a big role, the first choice is: change the battery place, strengthen the air circulation, the use of cold equipment.

Semi-annual and annual inspection of batteries

Electrode temperature:

Floating charging voltage of a single battery: