News

Installation and maintenance of box-type substations

Release time:

May 29,2023

Source:

Network

The installation, acceptance, handover test, commissioning, operation and maintenance of box-type substations should abide by regulations of the power authority, and the following issues should be noted: After receiving the commodity, the user should carefully check the commodity and should store the commodity in a proper place according to the normal use condition, if the product is not used temporarily. The product should be lifted by using a dedicated lifting tool at its bottom. The product should be placed horizontally on a foundation prepared in advance, four anchor bolts are installed (pouring for two times can be adopted), and the joint between the product base and the foundation should be sealed with cement mortar to prevent rainwater from entering the cable room. The high and low voltage cables should be introduced via the bottom sealing plate in the high and low voltage chambers. The joint between the cable and the cable pipe should be sealed and waterproof. Regardless of whether overhead or cable incoming lines are used on the high-voltage side of a box type substation, obviously visible breakers (such as drop-out fuses) should be set for the incoming line (overhead line or cable line) on the high-voltage side nearby the substation. In such a way, the operator can clearly know whether the inside space of the substation is charged. After the product is installed, reliable grounding should be guaranteed: Two main grounding terminals on the channel steel of the base of the substation, the neutral point and housing of the transformer and the pile head under the lightning arrester should be grounded respectively by the installation department. One group of grounding devices should be shared. The grounding resistance should be less than 4 Ω, and there should be no less than two grounding leads from the grounding grid to this product.

After the box-type substation is installed or repaired and before it is put into use, the following test and inspection should be performed. After the product is installed or repaired and before it is put into use, the following test and inspection should be performed. It should be checked whether it is clean inside the substation. It should be checked whether the operation mechanism is flexible. It should be checked whether the main electrical appliances can be turned on/off flexibly and reliably. It should be checked whether the auxiliary contact of the electrical appliances can be turned on/off reliably and accurately. It should be checked whether the meter and relay can work accurately and correctly. It should be checked whether the transformation ratio and wiring polarity of instruments and transformers are correct. It should be checked whether all the nuts of appliances are fastened and whether the installation is firm and reliable. It should be checked whether the bus connection is in good condition and whether its supporting insulator and clamping pieces are installed reliably. It should be checked whether the setting value of the electrical appliance meets requirements and whether the specification of the fuse core is correct. It should be checked whether the contact of the main circuit and auxiliary circuit can meet requirements of the electrical schematic diagram. The resistance of the grounding protection system inside the product should be less than 0.01 Ω. The voltage withstanding test of each part should be performed according to the corresponding voltage grade.

All the components in the box-type substation should be maintained according to the respective technical requirements. If the oil-immersed transformer is used, oil sample analysis and inspection should be conducted at least once a year according to requirements. After 20 times of on-load or 2000 times of no-load turning-on/off operation of the running high-voltage switchgear, the contact condition and the degree of loss of the arc extinguishing device should be checked. They should be timely repaired or replaced if any abnormality is found. After the low-voltage switchgear trips automatically, the cause of the trip should be inspected and analyzed, and the switchgear cannot be put back into operation before troubleshooting. One time of preventative test should be performed for the lightning arrester before the storm season comes every year. The incoming switch of the substation must be turned off before repair of the high-voltage switchgear or the overhaul.

Keywords:

Installation and maintenance of box-type substations

There is an urgent need for transformers in smart grid construction

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There is an urgent need for transformers in smart grid construction

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