Use and Improvement of Mine Flameproof Vacuum Breaker BGP_(9L)-6A

The use of mine explosion-proof vacuum circuit breaker BGP9L-6A and improvement of the existing problems in Zhang Haicheng (Yangquan Coal Industry Group, Yangquan, Shanxi 045000), and proposed an improvement method.

Mine explosion-proof vacuum circuit breaker is a key equipment in the coal mine underground 6kV power supply system. It can be distributed in the underground central substation, can also supply power to 6kV high-voltage electrical equipment and various transformers, and can also pass mining areas and work surfaces. The mobile substation supplies power to mining equipment for fully mechanized mining and fully mechanized excavation work surfaces. The performance of mine flameproof vacuum circuit breakers used in underground coal mines directly affects the quality and safety of power supply and distribution in underground coal mines.

In the early 1980s, the 6kV high-voltage power distribution equipment in coal mines continued to use the PB series of mine flameproof high-voltage circuit breakers; in the mid-1980s, the BGP series of mine flameproof types that were designed and manufactured in China were successively used in coal mines. High voltage vacuum power distribution device. According to statistics, by the early 1990s, there were more than 40 different types of BGP series high-voltage vacuum power distribution devices produced throughout the country. These products have roughly the same performance indicators, but their appearance, size, and choice of electrical devices Differently, it brings a lot of inconvenience to underground coal mine installation and maintenance management.

For the BGP series of mine explosion-proof high-voltage vacuum power distribution devices, the types of messy, can not be mixed, parts can not be exchanged and the problems in use, in 1994 the former Ministry of Coal Industry examined and passed the General Research Institute of Coal Science. The joint design and construction drawings of mine explosion-proof high-voltage vacuum power distribution equipment (hereinafter referred to as mine flameproof vacuum circuit breaker) and BGP9L-6A jointly designed by Shanghai Branch and Shenyang Electric Drive Research Institute are manufactured by Xiangtan Coal Mine Machinery Plant. .

Soon afterwards, Taiyuan Jixi Machinery Factory and Zhangzhou Dongfang Electromechanical Co., Ltd. and other units also successively produced different types of products. From May 1997 to October 2002, Yangquan Coal Mining Group used 264 sets of BGP9L*6A explosion-proof vacuum circuit breakers for mining. Through the use of the BGP9L*6A Mine Flameproof Vacuum Circuit Breaker in recent years, the Group has conducted tests on the following aspects.

1 Main technical parameters 5kA (rms) Rated short-circuit switching current 31. (peak) 2 Characteristics and existing problems 2.1 Main features Through 2a multi-time use, the author believes that BGP9L*6A mine flameproof vacuum circuit breaker has the following advantage.

The product has a well-designed layout. The electrical components are mounted on a movable trolley. The disconnectors are plug-in type. The cabinet adopts two screws with small screws and quick opening. The interlocking mechanism is reliable and easy to maintain.

The structure of the isolated vacuum circuit breaker is relatively reasonable, the closing mechanism is manual and electrically compatible, and the operation and use are convenient.

Compared with the BGP series of flameproof high-voltage vacuum power distribution equipment for mining, it has the characteristics of small size, light weight, complete protection function and stable and reliable performance.

22 Existing Problems The BGP9l-6A Mine Flameproof Vacuum Circuit Breaker has the following problems in use.

a No fault trip blocking function is set in the electric closing circuit, that is, after the fault trips, the instantaneous closing can still be repeated without resetting, which may cause an increase in electrical accidents, and the same exists in the manual closing circuit. problem. The electrical principle of the BGP9L-6A mine flameproof vacuum circuit breaker is as shown.

BGP9L*6A Mine Flameproof Vacuum Circuit Breaker Electrical Schematic When the 6kV disconnector is closed, the secondary side of the voltage transformer (TV secondary side) has AC 100V voltage, and the rectifier bridge output is output through Di~D6 three-phase bridge rectifier. The DC voltage of 130V is applied to the DC motor M via the normally closed contactor Q3 of the circuit breaker and the closing button SBi. When electric closing is required, the closing button SB1 is pressed, the circuit breaker starts to store energy and the closing operation is completed, and then Q3 automatically cuts off the closing power. When the 6kV line fails and the switch trips, Q3 automatically closes. If the SB1 closing button is pressed at this time, the mine can be instantaneously closed by the flameproof vacuum circuit breaker, which makes it easy to extend the fault range, injuring people by electric shock, and affecting the power supply security.

b. According to the GB3836*93 "Explosion Proof Electrical Apparatus Standard for Explosive Gas Environments", the electrical clearance of 6kV electrical equipment shall not be less than 60mm, and the bottommost phase of the BGP9L*6A Mine Flameproof Vacuum Circuit Breaker The gap between the conductive rod and the shell is only 30mm. If the corresponding measures for reinforced insulation are not taken, the explosion-proof standard cannot be met. This may cause the 6kV to discharge to ground due to insufficient clearance and trip the high voltage circuit breaker.

C. BGP9L*6A mine flameproof vacuum circuit breaker integrated protection device, also found some quality problems in use. If the aviation plug reliability is poor, the inner sleeve of the plug is easily damaged; the U1 and D1-D6 rectifier bridges in the protection device are burned many times; the leakage plug-in and the insulation monitoring plug-in have also been burned many times; the overload protection is adjusted according to the calculated value, and the switch cannot be normal. In operation, there is a refusal to operate, and the calculated value of the overload protection must be calculated and amplified to the 2nd to 3rd position before normal overload protection can be achieved.

3 Solution In order to solve the fault trip blocking, a JQX*10F3C type relay is installed in the DC 24V loop, and a set of normally closed contacts are added to the closing motor loop and the voltage loss loop to ensure that the main loop is in a fault state. Under the electric reclosing, as shown.

The improved electrical schematic diagram of the BGP9L*6A Mine Flameproof Vacuum Circuit Breaker has improved the above-mentioned control loops. Although the drawbacks of the electric instantaneous reclosing can be solved under fault conditions, manual reclosing cannot be avoided. For the safety of power supply, the on-site operator is strictly required to observe the open circuit state display after the circuit breaker trips. If it is displayed as a short circuit or leakage, manual reclosing is forbidden. Only when the fault is completed, the reset button can be pressed to perform manual and electric operation. Switch on.

All the conducting bars of the BGP9L*6A mine explosion-proof vacuum circuit breakers in the rear wiring chamber are equipped with high-voltage insulation bushings to make up for the lack of electrical clearance.

The circuit breaker is initially integrated protection device, the overload protection unit is 4 anti-time curve, overload delay time is 1st gear is 0.5s~2s, 2nd gear is 2s 3 gear is 5s 4 gear is 8s~11s if overload is set When the value is adjusted to 1. 5 times to 2 times of the rated value, when the larger equipment is started, the startup current exceeds the overload setting current and the start-up time exceeds the delay time of the overload protection. Therefore, in the 1st gear, In the delay time range of 2nd and 3rd gears, since the delay time does not escape from the startup time of the device, a malfunction may occur, so only the 4th curve can be used. And on the actual timing of the site, it is not easy to grasp which curve to choose. In addition, the leakage protection unit of the comprehensive protection device, setting current is 0.5A~6A, delay time is 0.1s~1.5s, due to mine cable network is very long, large capacitance current, aging cable, insulation reduction and other reasons, the power grid Leakage protection units often malfunction, and after the operation can not find the cause, after a period of time, once the power is restored to normal, leakage protection unit does not achieve leakage protection. If the setting value and the delay time are adjusted according to this setting value, misoperation may occur and even cause electric shock to the human body. Therefore, in practice, the leakage protection unit should be replaced with a ground protection unit.

The overload protection unit is redesigned from the original four inverse time curves to an inverse time curve, making the setting method simple and easy to operate, and the operation is reliable. When the overload current is set at 6.0 times, the delay time is more than 8s, thus avoiding the overload protection malfunction when the large equipment starts. The original leakage protection unit was also changed to the grounding protection unit, zero-sequence current was set to 0. ~10A sub-range adjustable, action time is set to 0.1s~8s sub-range adjustable, thus avoiding the downhole high-voltage system due to protection Sensitive and often mistaken actions affect production. In the selection of components and components, strict screening and aging tests are required, so that the thermal stability of protection is good, the plugging is secure, and the mechanical strength meets the requirements.

The newly-developed PBZB-L2 high-voltage comprehensive protector and the BGP9L-6A mine flameproof vacuum circuit breaker have perfect performance, sensitive and reliable action, convenient adjustment and maintenance, and rarely malfunction, and can meet the protective effect of 6kV power grid safety power supply. .

In recent years, through the use of BGP9L-6A mine flameproof vacuum circuit breakers, some improvements have been made to the existing problems. Its overall performance is relatively good, and it can meet the needs of 6kV underground power supply and distribution in coal mines.

This article editor Liu Dawei (continued from page 50) and other advantages, so the proportion of trackless auxiliary transport equipment in China's coal mine underground transportation will expand year by year, the prospects are good. At present, imported equipment still dominates the auxiliary transportation equipment market in China's coal mines and occupies 3/4 of the domestic trackless auxiliary transportation market. With the increasing development and expansion of domestic research and manufacturing units, continuous improvement in the level of research, completeness and variety of varieties, and its many advantages such as low prices and timely service, the proportion of imported equipment will decline year by year. In addition, with the development of high-yield and high-efficiency modern mines in China, the current R&D and production capabilities are far from meeting the needs of underground coal mines for auxiliary transportation. It can be seen that the market development prospects for underground trackless auxiliary transport equipment are quite broad.

In recent years, China's coal mine equipment and technology have been greatly improved and improved, providing a strong guarantee for accelerating the development of underground trackless auxiliary transportation technology.

4 Conclusion The market for underground trackless auxiliary transport equipment has broad prospects for development. No matter whether it is for R&D, design, manufacture, or testing, the capability needs to be strengthened, enriched, and improved. The state should give preferential policies and support in this regard.

Although China has made great progress in the development of transport, cargo, passenger and cargo dual-use vehicles and modified vehicles, it has a wide gap compared to the advanced countries in the world. It should carry out standardization and serialization as soon as possible. At the same time, it will increase the research and development of the scraper vehicles.

Accelerate the research of general and key technologies.

While continuously developing and perfecting the explosion-proof diesel engine, it is necessary to increase the research and development of the traction power vehicle with small air pollution and high power in the roadway.

This article editor Liu Dawei

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