Industrial Technology China New Technology New Product bookmark0 Brief Introduction of Substation Electrical Equipment Installation and Commissioning Tang Heng (Yunnan Transmission and Distribution Engineering Company, Kunming 650216, China) The quality of electrical equipment installation is directly related to the power system. The normal and safe operation of itself. In this paper, based on the example of a substation, a detailed analysis of the installation and commissioning of electrical equipment is provided for the relevant technical personnel.
The substation has a mild climate, a flat terrain, geological conditions, and convenient transportation.
The project is based on the design of steel reinforced concrete columns, rubble bars, the main structure of brick concrete and reinforced concrete frame structures, and cast-in-place reinforced concrete buildings (houses). The construction water is led to the mixing field and construction site by D50 water pipe, and according to the actual situation, it needs to be equipped with an activity water tank to ensure sufficient water. The construction power line adopts the zero-connection protection system to connect construction power to the construction site.
In order to ensure that the project is completed on schedule, this requires close cooperation between the electrical and civil works, reasonable scheduling and construction of technical force and the development of detailed and feasible quality and safety control measures to ensure that the project is of high quality, safe and on schedule. In addition, we must effectively protect the finished products, reduce rework, and increase efficiency. If there is any discrepancy between the construction drawings and the actual situation during the construction, it shall be promptly put forward, and be in timely contact with the design, Party A and the supervision and resolution.
The preparation of busbar installations is a very important task that directly affects the progress and quality of construction. Therefore, it must be given the necessary attention. When the busbars are installed, they need to be corrected, twisted and bent. Some special tools are also needed. Some of these tools cannot be purchased on the market and must be made on their own. They should be properly prepared before the busbars are installed. These special tools are mainly bus correction machines, flat bending machines and vertical bending machines.
Hard busbars are transported from the manufacturing plant to the construction site, and some busbars may bend and deform. If there are few, you can use manual correction, when there are many, in order to improve work efficiency, you can create a simple bus correction machine. It is only necessary to place the Spring-corrected uneven busbars on the corrector, then operate the jacks and use the power of the jacks to correct the busbars.
Lift the handle when the busbar flat bending machine is bent, and put the busbar that needs to be bent between the two rollers 2 of the flat bending machine. The bending part is placed on the roller shaft. After correcting, tighten the gantry pressure Screw 3 and slowly press the flat The handle of the bender causes the busbar to bend. When operating, care should be taken not to force too much, so as to avoid bus cracks. When the busbar bends to a certain degree, a check can be made with the template for proper bending.
During the laying of power cables, it should be noted that the bending radius of the cables should meet the specification requirements. The number of cables to be identified is sufficient, and the starting end, direction, model number, and specifications are clearly identifiable. During the laying process, the paper-insulated or fully-plastic insulated cables of 35kV and below shall be laid at an average minimum temperature of not less than 0°C. If they are to be laid, they shall be preheated by applying low-voltage current or increasing ambient temperature. However, it is forbidden to directly bake the cable with flame. When laying, prevent excessive bending and spraining of the cable. The ratio of the cable bending rate to the outer diameter of the cable should not be less than the following: Oil-impregnated paper-insulated power cable, lead package 15 times, aluminum package 25 times; plastic insulated cable.
When installing the transformer, special attention should be paid to checking whether the high-voltage wire package is damaged or displaced, whether the high-voltage insulator is scratched or damaged, and whether the humidity control device includes the humidity display instrument. During the construction process, it is strictly forbidden that any debris should fall into the transformer body. The body iron core and the box body must be reliably grounded. The work grounding section should meet the requirements of the code, and at least not less than the cross section of the grounding trunk in the substation. Transformer in place should look for the direction of the high and low pressure side, must not be mistaken. Transformer body should be placed horizontally, its installation level tolerance allows 2%, vertical tolerance is 1.5%. According to the transformer factory requirements, in place after the installation of transformer isolator, and then on-load regulator, temperature measuring device , control box and other accessories for installation.
Check the insulation of the circuit breaker for cracks; check the circuit breaker operating handle for cracks; check whether the signal indication of the circuit breaker is consistent with the state of the circuit. Remove the four-point fixing screw of the circuit breaker with 4 screwdrivers; remove the upper cover of the insulation cover of the circuit breaker and the three-phase arc extinguishing cover of the circuit breaker; install the three-phase arc extinguishing cover of the circuit breaker: buckle the upper cover of the insulation cover of the circuit breaker; The four corners are fixed with screws. Close the circuit breaker and observe whether the circuit breaker indication is in the “closed†position. Disconnect the circuit breaker and observe whether the circuit breaker indicator is off. When installing, it is necessary to pay attention to the operation handle and the linkage drive mechanism cannot have any frame during movement. Quantity and transmission clearance. Therefore, it is best to use a taper pin to attach the adjustment operating mechanism. When the 10kV indoor disconnection switch operating mechanism is connected with the connecting rod and the shaft, it can be equipped with drilling, tapping, and then bolted. In the installation process of the operating mechanism, it is necessary to make the position and size of each supporting bearing accurate, and to ensure that the operating mechanism and the connecting rod are not subjected to any resistance other than the operating force.
Check the wire, gold has no damage, is smooth, and the connector has no overheating. In order to determine whether there is heat at the bus joints, whether the busbars are painted or the temperature change film should be observed. For joints with large currents, the temperature at the joints can be measured with an infrared thermometer. When the test results exceed the following values, the load should be reduced. Or stop running, bare busbars and joints at 70 °C, contact surface with a tin coating of 85 °C, with a silver coating of 95 °C, flash soldering at 100 °C. Each interval of six months to one Annual bus and insulator cleaning, especially in dirty areas, should increase the number of sweeps. At least once every two years, check the tightening of various types of clamps.
With the test and maintenance of the power distribution device, check the fastening and integrity of the bus joints and fittings, and repair the defective components in time.
In the spring and autumn of each year, the indoor and outdoor cable terminal heads are inspected to remove dust and oil, and check whether the insulation casing is damaged or not, and whether the joints are overheated, oil flowing, or glue flowing.
Every week should go along the cable to go through a circuit inspection. Replace the damaged stakes, replace the damaged cover, fill the pits, and plug the infiltration outlets of the cable ducts.
Surveillance of personnel shall be provided for the earth around the cable to prevent excavation and breakage of electric cables and personal electric shock.
When measuring the resistance of adiabatic insulation or performing preventive tests, the connectors at both ends of the cable must be opened with a clean cotton rag to clean the dust and oil on the terminal head in order to obtain accurate test results.
3.3 Power transformer debugging content Measure the DC resistance of the winding, 25MVA three-phase transformer, the mutual difference of each phase measured value should be less than 2% of the average value, the mutual difference between the measured values ​​of the line should be less than 1% of the average value Check that the transformer ratio of all taps is not significantly different from that of the manufacturer's nameplate, and that it should comply with the law of transformer ratios; check the three-phase connection of transformers should meet the design requirements and the marking on the nameplate; The winding insulation resistance and absorption ratio, insulation resistance value should not be less than 70% of the product's factory value, the absorption ratio should not be significantly different from the product's factory value, and should not be less than 1.3 at normal temperature; measure the insulation resistance of insulated rod, Insulation resistance of insulated rods made of organic materials, measurement points, DC resistance and insulation resistance of closing coils, DC resistance measurement of each phase conductive loop, measurement of the time for the opening and closing of circuit breakers, and measurement of the main contacts of circuit breakers. Simultaneous closing, measuring the bounce time of the contactor when the circuit breaker is closed, measuring the minimum operating value of the circuit breaker sub, closing the coil, and the power frequency withstand voltage test.
When the switch is commissioned for the first time, the switch should be closed and opened slowly.
When the brake is closed, the lateral impact of the contact knife should be observed. If there is an impact, the position of the contact should be changed so that the contact blade is just inserted into the contact. The depth at which the blade is inserted into the contact should not be less than 90% of its width, but it should not be so large as to impinge on the end of the insulator. The bottom gate of the contact knife and contact should be kept 35mm clearance, otherwise the straight connection head should be adjusted to change the length of the connecting rod, or adjust the brake screw on the switch shaft, and change the rotation angle of the shaft to adjust the depth of the penetration knife insertion. Adjust the spring pressure on both sides of the contact knife so that the contact condition is in compliance with the regulations (check with O.05mmX10mm feeler gauge, the plug shall not enter when the wire touches, and the inserting depth when making surface contact: when the contact surface width is not more than 50mm, More than 4mm; contact surface width not less than 60mm, should not exceed 6mm).
The primary equipment in the main circuit of the power supply system, which is responsible for the transmission, transformation and distribution of electrical energy, is the main equipment for direct production, transformation, transmission and distribution of electrical energy. Installation and commissioning must be conducted in strict accordance with national standards and regulations. Next, innovatively develop, learn from, and cite new types of construction processes and construction methods to ensure the reliable operation of primary equipment in power plants and substations.
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