Fault Handling Of Box Type Substation

Fault handling of box type substation

Precautions for outdoor installation of box type substations

1. The grounding conductor of the box type substation must be copper, and the cross-sectional area must not be less than 30mm2. For some equipment that intentionally reduces the size of the grounding conductor, it is easy to suffer lightning damage to the equipment.

2. The grounding network of the box type substation also needs to ensure sufficient coverage area and depth. The grounding network of the box type substation should preferably be buried 1 m below the ground. In order to reduce the resistance, some vertical Earth electrode should also be added.

3. Box type substations should be installed in areas without strong vibrations and impacts, and there should be no significant electromagnetic induction nearby. The cable entry and exit lines should meet the construction safety distance.

4. The installation of box type substations should be in a dry and ventilated area, installed horizontally, with a slope not exceeding 5 degrees.

5. The installation area of the box type substation shall not have hazardous substances such as explosions, as well as the presence of corrosive gases or liquids.

6. The outdoor use of the box type substation does not require duty, so it occupies a small area and has low operating costs.

Common electrical fault handling measures for box type substations

1. Measures for overheating treatment of box transformers. Overheating of electrical equipment in box type substations for a long time can easily lead to insulation aging, which in turn leads to loose joints. Internal short circuits in box substations can also cause temperature increases and even trigger fires. The transformer winding is also prone to heating during operation, and continuous heating can easily damage the transformer. In response to the problem of overheating in box type substations, it is necessary to promptly clean up residual substances such as dust inside the substation. Secondly, it is necessary to strengthen temperature monitoring of various equipment inside the box transformer and issue timely high-temperature warning signals.

2. The load switch of the box transformer is faulty. In box type substations, load switches rarely fail due to their own faults. The main reasons for the failure of the on load switch are as follows: firstly, the switch has been used for a long time, causing deformation of the switch frame, resulting in the switch becoming loose and falling off; Secondly, the strength of the components is not satisfactory, resulting in damage to the tap changer during switching operations; The third reason is that the quality of the switch is not up to standard, and after using it for a period of time, there are situations such as spindle breakage. To ensure the stable operation of the box transformer, the production process requires strict selection of on-load switches, ensuring the quality of the switches and the installation process.

3. The low-voltage switch of the box transformer has tripped and failed. There are two main reasons for the tripping of the low-voltage switch in the box transformer, one of which is a busbar fault; The second is switch misoperation, etc. In case of low-voltage switch tripping fault, it is necessary to carefully inspect the box transformer. Once overcurrent protection occurs on the low-voltage side of the main transformer, relevant equipment needs to be immediately inspected and protected reasonably. At the same time, eliminate the malfunction of switch misoperation, focusing on whether it is a busbar fault or a line fault. Further inspect the relevant equipment to see if there is any leakage in the protective pressure plate of the equipment being used. If necessary, use professional equipment for inspection.

Maintenance of tripping faults in box type substations

1. During the operation stage of a box type substation, there are mainly two types of faults: main transformer switch tripping and line switch tripping. The main transformer switch tripping is further divided into three side tripping faults of the main transformer and low-voltage side tripping faults of the main transformer. The determination of the cause of transformer tripping in a box type substation mainly relies on the analysis of various monitoring data.

When a tripping fault occurs in an outdoor box type substation, maintenance personnel should rush to the site as soon as possible to restore power. The maintenance personnel first check if there is serious damage to the equipment, and then check the operation of the trip switch and arc suppression coil. For spring energy storage switches, it is necessary to check whether the spring energy storage is faulty. For electromagnetic switches, the main check is the switch power fuse.

When the low-voltage tripping fault occurs in the main transformer of the box type transformer, the main focus is to inspect the line protection and main transformer protection in the substation equipment to find the cause of the accident. When overcurrent protection on the low-voltage side of the transformer is the only cause of the fault, the line fault can be eliminated, and then the output terminal can be inspected, followed by the inspection of the substation equipment. When there is also line protection on the low-voltage side of the transformer for overcurrent protection, it can be directly determined as a line fault based on whether the line is disconnected. Maintenance personnel not only need to check the outlet position of the line, but also the entire line. Only after the line fault is eliminated can the opening and closing trip fault be handled.

Precautions for Fire and Explosion Protection Operation of Box Substation

1. Box type substations cannot operate under long-term overload, especially after a few years of use, attention should be paid to issues such as coil aging and insulation aging to prevent short circuits from occurring.

2. If an oil immersed transformer is installed in a box type substation, it is also necessary to regularly check the insulation performance of transformer oil, and replace the unqualified transformer oil in time.

3. During the operation of prefabricated substations, the operation status of the transformer should be monitored at all times to prevent insulation aging caused by long-term heating of the transformer core. During maintenance, attention should also be paid to not damaging the insulation layer.

4. During daily maintenance of box type substations, attention should be paid to wire contact issues and timely handling of poor contact wires.

5. Lightning arresters are installed on the high-voltage switchgear, transformers, and low-voltage switchgear of prefabricated box substations to prevent lightning damage to related equipment and protect the safe operation of the box substation.

6. During the design phase of the box type substation, it is necessary to consider the ventilation and heat dissipation situation, design sufficient ventilation openings and exhaust fans. The purple light box type substation is equipped with exhaust fans in both the transformer and low-voltage rooms, and the transformer room has an automatic temperature monitoring system that can effectively control the temperature inside the box type substation.

epilogue

Box type substations are usually installed outdoors and are left unattended all year round. Only through regular inspections every year can a comprehensive maintenance of the box type substation be carried out. The maintenance of box type substations is a dangerous task, and it is even more important to pay close attention to safety when conducting live maintenance. The maintenance work of the box transformer is complex, cumbersome, and requires a large amount of work. If engaged in this work for a long time, it can easily cause mental paralysis and cause power accidents. Therefore, it is necessary to strengthen the safety education work of the operation and maintenance team. The lifespan of box type substations is usually 10-20 years, with a maximum lifespan of up to 20 years for Purple Light box type substations. Regular maintenance of the box substation is essential for its normal operation

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