Transition method of traction substation transformer from direct power supply to AT power supply in operating line

Abstract

The present invention provides a method for transitioning a transformer of a traction substation from direct power supply to AT power supply on an operating line, which belongs to the technical field of power supply for electrified railways and includes the following steps: S1, construction site measurement; S2, erection of transition portal frames and neutral point brackets; S3, construction of transition foundation for existing main transformers; S4, laying of transition cables and production of cable heads; S5, removal of soft busbars and equipment leads of existing main transformers; S6, reverse connection of secondary circuits; S7, displacement of existing main transformers to be transitioned and corresponding existing neutral point devices; S8, laying and wiring of high-voltage cables; S9, testing of existing main transformers after transition; S10, power transmission impact and operation of existing main transformers after transition. The present invention can complete related work safely and efficiently without affecting traffic and normal operation of equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of electrified railway power supply, and specifically discloses a method for transitioning a traction substation transformer from direct power supply of an operating line to AT power supply. Background Art

[0002] In the electrified railway system, the traction substation is the core part of the traction power supply system. It converts the three-phase high voltage electricity transmitted from the power system into traction power for the operation of electric locomotives through voltage reduction. The main electrical connection can reflect the operating performance of the traction substation, so the safety, reliability, economy and flexibility of the traction substation are particularly important. In order to reduce the interference to the communication lines, most of the power supply methods basically adopt AT power supply or direct power supply with return line. Technically, both AT power supply and direct power supply with return line can meet the high-speed traction of 300KM / h and above. Compared with the two, AT power supply is more adaptable to the power supply of large power loads, and the number of electrical phases is reduced.

[0003] Therefore, when the traction power supply system has insufficient power supply capacity and needs to be expanded and renovated, the direct power supply mode with return line is converted into AT power supply mode. This can double the feed voltage without improving the insulation level of the traction network, and exponentially increase the power supply capacity of the traction network, thereby expanding the distance between traction substations.

[0004] However, when transitioning existing transformers during capacity expansion and transformation, the following technical problems arise:

[0005] 1. According to the on-site construction conditions of the traction substation, the large crane used for the main transformer relocation is large in size and has a small space inside. It is easy for the large crane to damage the equipment when it rotates. At the same time, it is easy for the large crane to lift at too fast a speed or inaccurately position during the lifting process.

[0006] 2. Complete the transition of the existing main transformer within the specified time. There are problems such as limited construction time, large project volume, and complex and changeable construction site. In addition, the normal operation of the equipment must be ensured during the construction process without affecting the normal operation of the train. Summary of the invention

[0007] The present invention provides a method for transitioning a traction substation transformer from direct power supply of an operating line to AT power supply, which at least solves one technical problem described in the background technology.

[0008] The above-mentioned method for transitioning the transformer of the traction substation from direct power supply of the operating line to AT power supply comprises the following steps:

[0009] S1, construction site survey

[0010] Conduct on-site surveys based on construction drawings to determine the locations of new and existing equipment and make proper markings;

[0011] S2, Transition door frame and neutral point support installation

[0012] t1. According to the construction site survey, determine the position of the transition portal frame and the existing neutral point, cast the foundation of the transition portal frame and the existing neutral point in advance, and maintain the foundation to ensure that the foundation bearing capacity meets the requirements;

[0013] t2, install the transition door frame on the basis of the transition door frame, set up supporting insulators and lightning arrester I on the transition door frame, and install the neutral point bracket on the existing neutral point;

[0014] S3, existing main transformer transition foundation construction

[0015] Laying transverse sleepers and longitudinal sleepers at the existing main transformer transition position determined in step S1, and laying steel plates on the transverse sleepers and longitudinal sleepers as the existing main transformer transition foundation;

[0016] S4, transition cable laying and cable head production

[0017] t1. According to the on-site investigation and in combination with the construction drawings, determine the number, model specifications, voltage circuit, and control circuit of the transition cable, and lay the transition cable. One end of the transition cable is used to connect the existing main transformer protection panel, and the other end is used to connect the existing main transformer body box and the existing neutral point device operating mechanism box;

[0018] t2, make the cable head of the transition cable, and do not connect the wires for the time being;

[0019] S5, removal of existing main transformer soft busbar and equipment leads

[0020] Select an existing main transformer as the existing main transformer to be transitioned, put the existing main transformer to be transitioned in standby state, and other existing main transformers in operation state. In the skylight point, remove the soft busbar above the existing main transformer to be transitioned and the portal frame crossbeam of the existing main transformer to be transitioned, the high-voltage bushing connection line and the low-voltage bushing connection line of the existing main transformer to be transitioned, the circuit breaker lead-down line corresponding to the existing main transformer to be transitioned, the grounding connection flat steel of the existing main transformer to be transitioned, the return connection flat steel of the existing main transformer to be transitioned, and the existing neutral point device connection flat steel corresponding to the existing main transformer to be transitioned;

[0021] S6, secondary circuit reverse connection

[0022] In the skylight point, remove the operating mechanism box of the existing neutral point device corresponding to the existing main transformer to be transitioned, the existing main transformer body box, the existing main transformer outdoor terminal box and the related wiring of the existing main transformer protection panel;

[0023] S7, the existing main transformer and the corresponding existing neutral point device to be transferred

[0024] t1, laying the shift track between the existing main transformer to be transferred and the transition foundation of the existing main transformer, and using the electric hydraulic manual shifting method to shift the existing main transformer to be transferred to the transition foundation of the existing main transformer;

[0025] t2, after the existing main transformer is in place, restore the existing main transformer body box, the existing main transformer outdoor terminal box and the existing main transformer protection panel related wiring, and restore the jumper between the existing main transformer and the circuit breaker after the transition is completed;

[0026] t3, relocate and install the existing neutral point device, install the operating mechanism box, lightning arrester II, current transformer and disconnector of the existing neutral point device onto the built neutral point bracket, and restore the wiring;

[0027] S8, High voltage cable laying and wiring

[0028] Lay high-voltage cables and connect them to the existing low-voltage bushings of the main transformer along the transition portal frame;

[0029] S9, test of existing main transformer after transition is completed

[0030] Carry out body test and protection test on the existing main transformer after the transition is completed;

[0031] S10, the existing main transformer power transmission impact and operation after the transition is completed

[0032] Apply for a power outage for the entire station within the skylight point, and conduct a power surge to the existing main transformer with high-voltage cables that have completed the transition. During the power surge of the existing main transformer, open and close the circuit breaker and disconnector in the control room;

[0033] S11, the skylight point ends, the existing main transformer that has completed the transition is put into operation, and steps S5-S10 are repeated to transition the next existing main transformer.

[0034] In step S1, firstly, the insulation distance between the displaced position of the existing main transformer and the live equipment is ensured, and secondly, the displaced position of the existing main transformer is ensured not to affect the foundation excavation of the new equipment.

[0035] In step S4, when the transition cables are laid, they do not cross each other, and spare lengths are left at the terminals and wall bushings; when the transition cables enter and exit cable trenches, grooves, and buildings, the entrances and exits are sealed with fireproof materials; the bending radius of the transition cables is not less than 15 times the diameter of the transition cables.

[0036] In step S6, a multimeter is used to test whether the operating mechanism box of the existing neutral point device, the existing main transformer body box, the existing main transformer outdoor terminal box and the existing main transformer protection panel are energized and records are kept. After confirming that they are not energized, they are removed.

[0037] In step S8, the high-voltage cable clamp is made of aluminum.

[0038] In step S10, the power supply impulse test is carried out twice. The first impulse test lasts for a preset time, and the oil temperature and oil level are recorded. After the first impulse test is successful, the high-voltage room busbar is tested to confirm whether there is electricity and check whether there is any abnormality in the equipment.

[0039] After the first impact test is completed, the second impact test will start at a preset time interval. Before the second impact test, the feeder side disconnector will be moved to the open position and the circuit breaker will be moved to the closed position. The second impact test will last for a preset time. After the second impact test is successful, observe whether the bus voltage is normal. After the impact is completed, restore related equipment.

[0040] Compared with the prior art, the present invention has the following beneficial effects.

[0041] 1. Combined with the on-site conditions, the main transformer transition shift adopts the method of electric hydraulic manual shifting. This method is relatively environmentally friendly, reduces the number of construction machinery and vehicles, and minimizes interference during construction.

[0042] 2. Combined with the site and construction drawings, the foundation of the new main transformer is implemented at the location of the existing main transformer foundation. The existing main transformer position needs to be transitioned. During the transition, the two existing main transformers are in a state of one standby and one in operation. The skylight point is used to transition the standby existing main transformer. During the transition of the existing main transformer, sleepers and steel plates are used to build the transition foundation, high-voltage cables are used instead of soft busbars, and lightweight transition portal frames are used instead of existing high-column portal frames. After the transition of the standby main transformer is completed, the next skylight point is used to perform power supply shock on the existing main transformer that has completed the transition. After the shock is completed, the skylight point ends the existing main transformer that has completed the transition and is put into operation. Then the next skylight point is used to transition the next existing main transformer. The transition process is the same as the previous existing main transformer. After the transition of the existing main transformer is completed, the old foundation is removed and a new foundation is constructed to meet the installation requirements of the new main transformer. The entire construction process takes less time, has a small amount of work, and the construction site is simple and controllable. In addition, the normal operation of the equipment can be guaranteed during the construction process without affecting the normal operation of the train. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 Flow chart of the method for transitioning the transformer of the traction substation from direct power supply to AT power supply for the operating line;

[0045] Figure 2 It is the transition position diagram of the existing main transformer;

[0046] Figure 3 This is the installation main view of the transition door frame;

[0047] Figure 4 This is the installation side view of the transition door frame;

[0048] Figure 5 This is the top view of the installation of the transition door frame;

[0049] Figure 6 This is the installation main view of the existing neutral point device;

[0050] Figure 7 This is the installation side view of the existing neutral point device;

[0051] Figure 8 It is the top view of the installation of the existing neutral point device;

[0052] Fig. 9 It is a structural diagram of the existing main transformer transition foundation;

[0053] Fig.10 This is the main view of the installation of high-voltage cables and wall bushings;

[0054] Fig.11 This is a side view of the installation of high-voltage cables and wall bushings.

[0055] 1-support insulator; 2-lightning arrester I; 3-H-shaped steel column; 4-steel top plate; 5-steel reinforcement plate; 6-bracket; 7-operating mechanism box; 8-lightning arrester II; 9-current transformer; 10-isolating switch; 11-steel plate; 12-sleeper; 13-transition cable; 14-wall bushing. DETAILED DESCRIPTION

[0056] This embodiment takes the transition construction of a traction substation transformer from direct power supply to AT power supply on a railway operating line as an example to describe the construction steps in detail.

[0057] S0, Construction Preparation

[0058] Read and review relevant construction drawings, design standards, and implementation construction organization design, conduct technical briefings for construction personnel, and provide pre-job technical training and safety training for construction personnel. Only after passing the assessment can they hold a certificate to work. Coordination work involved in construction operations and various external technical data, including the collection of relevant data such as lines and roadbeds, are required to facilitate the entry of equipment in the future.

[0059] S1, construction site survey

[0060] Conduct on-site surveys based on construction drawings to determine the locations of new and existing equipment and mark them.

[0061] Determine the position of the existing main transformer after displacement, first ensure the insulation distance from the live equipment (>1.7m), and secondly ensure that the position of the existing main transformer after displacement does not affect the foundation excavation of the new equipment (such as firewalls, new main transformers and supporting insulators), ensure the smooth progress of subsequent construction, and prevent rework. This embodiment places the existing main transformer 2 meters away from the 110kV circuit breaker, which fully meets the requirements.

[0062] S2, Transition door frame and neutral point support installation

[0063] t1. According to the construction site survey, determine the position of the transition portal frame and the existing neutral point, cast the foundation of the transition portal frame and the existing neutral point one month in advance, and maintain the foundation to ensure that the foundation bearing capacity meets the requirements;

[0064] t2. Install the transition gate frame on the basis of the transition gate frame, and set up supporting insulator 1 and lightning arrester Ⅰ2 on the transition gate frame to facilitate the laying of high-voltage cables and the connection between the high-voltage cables and the existing main transformer low-voltage bushings. Install the neutral point bracket on the existing neutral point basis.

[0065] The transition door frame includes an H-shaped steel column 3, a steel top plate 4, a steel reinforcement plate 5, and a bracket 6; two H-shaped steel columns 3 are arranged opposite to each other; the steel top plate 4 is fixed to the top ends of the two H-shaped steel columns 3; the steel reinforcement plate 5 is located below the steel top plate 4, and its two ends are respectively fixed to the two H-shaped steel columns 3; the bracket 6 is installed on the steel top plate 4; the supporting insulator 1 and the lightning arrester Ⅰ2 are installed on the bracket 6.

[0066] S3, existing main transformer transition foundation construction

[0067] The replacement of the main transformer is to install a new main transformer after building a new foundation at the original site of the existing main transformer. The existing main transformer needs to be transitioned. After the transition is completed, the old foundation will be removed and a new foundation will be built to meet the installation requirements of the new main transformer. The transition of the existing main transformer needs to solve problems such as site bearing capacity, insulation distance, and safe construction.

[0068] In order to make the hardened ground have sufficient bearing capacity to place the existing main transformer, through calculation, a layer of transverse sleepers and a layer of longitudinal sleepers (4 meters * 4 meters) are laid in front of the foundation of the existing main transformer, and steel plates 11 are laid above the transverse sleepers and longitudinal sleepers as the transition foundation of the existing main transformer. The stress points are dispersed by the steel plates 11 and sleepers 12, which solves the problem of transition placement of the existing main transformer on the hardened ground.

[0069] S4, transition cable laying and cable head production

[0070] t1. According to the on-site investigation and in combination with the construction drawings, determine the number, model specifications, voltage circuit, and control circuit of the transition cables 13, and lay the transition cables 13. When laying the transition cables 13, they do not cross each other. After laying, the transition cables 13 are arranged neatly, and spare lengths are left at the terminals and wall bushings 14. When the transition cables 13 enter and exit cable trenches, grooves, and buildings, the entrances and exits are blocked with fireproof materials, and the bending radius of the transition cables 13 is not less than 15 times the cable diameter;

[0071] t2. During the manufacturing process, the cable head of the transition cable 13 must comply with relevant process standards. One end of the transition cable 13 is used to connect the main transformer protection disk, and the other end is used to connect the existing main transformer body box and the existing neutral point separation mechanism box. The cable head is not connected for the time being, and rain protection measures are implemented for the cable head.

[0072] S5, removal of existing main transformer soft busbar and equipment leads

[0073] Select an existing main transformer as the existing main transformer to be transitioned, put the existing main transformer to be transitioned in standby state, and other existing main transformers in operation state. In the skylight point, remove the soft busbar above the existing main transformer to be transitioned and the portal frame crossbeam of the existing main transformer to be transitioned, the high-voltage bushing connection line and the low-voltage bushing connection line of the existing main transformer to be transitioned, the circuit breaker lead-down line corresponding to the existing main transformer to be transitioned, the grounding connecting flat steel of the existing main transformer to be transitioned, the return connecting flat steel of the existing main transformer to be transitioned and the existing neutral point device connecting flat steel corresponding to the existing main transformer to be transitioned.

[0074] S6, secondary circuit reverse connection

[0075] In the skylight point, remove the operating mechanism box 7 of the existing neutral point device corresponding to the existing main transformer to be transitioned, the existing main transformer body box, the existing main transformer outdoor terminal box and the related wiring of the existing main transformer protection panel; before removing the wiring, first use a multimeter to test whether it is energized and take photos to record it, and remove it after confirming that it is not energized.

[0076] S7, the existing main transformer and the corresponding existing neutral point device to be transferred

[0077] t1. Lay the shift track between the existing main transformer to be transferred and the transition foundation of the existing main transformer. Use the electric hydraulic manual shifting method to shift the existing main transformer to be transferred to the transition foundation of the existing main transformer. The existing main transformer to be transferred must not be damaged during the shifting process. Wrap the existing main transformer casing to be transferred with soft materials such as quilts;

[0078] t2, after the existing main transformer is in place, restore the existing main transformer body box, the existing main transformer outdoor terminal box and the existing main transformer protection panel related wiring, and restore the jumper between the existing main transformer and the circuit breaker after the transition is completed. The wiring requirements are as follows:

[0079] (1) Construction must be carried out strictly in accordance with the design drawings, wiring must be correct, and the electrical circuit connection must be reliable and firm;

[0080] (2) The cable core wires should be marked with loop numbers, the wiring should be neat and beautiful, the core wires should be well insulated and free of damage;

[0081] (3) The cables are arranged neatly and fixed firmly, and the armor layer of the armored cable does not enter the panel or cabinet;

[0082] (4) The cable cores are arranged regularly in a vertical or horizontal manner, and spare cores are appropriately reserved;

[0083] t3, the existing neutral point device is relocated and installed, and the operating mechanism box 7, lightning arrester II 8, current transformer 9 and disconnector 10 of the existing neutral point device are installed on the constructed neutral point bracket, and the wiring is restored. During the wiring process, special attention is paid to the secondary wiring of the current transformer 9, and the secondary side of the current transformer 9 must not be broken. After the installation of the existing neutral point device is completed, manual opening and closing should be performed to ensure that the disconnector 10 is opened and closed in place.

[0084] S8, High voltage cable laying and wiring

[0085] Lay high-voltage cables and connect them to the existing low-voltage bushings of the main transformer along the transition portal frame. The requirements for laying high-voltage cables are as follows:

[0086] (1) Do not damage the high-voltage cables;

[0087] (2) The high-voltage cable clamp is made of aluminum to prevent magnetic backflow;

[0088] (3) The connection between the high-voltage cable head and the wall bushing and the transition to the existing main transformer low-voltage bushing must be reliable and firm, and ensure that the high-voltage cable armor and shielding layers are well grounded.

[0089] S9, test of existing main transformer after transition is completed

[0090] The existing main transformer that has completed the transition is subjected to main body test and protection test. After the test is completed, the existing main transformer that has completed the transition is ready for emergency power transmission.

[0091] S10, the existing main transformer power transmission impact and operation after the transition is completed

[0092] Apply for a power outage for the entire station within the skylight point, and conduct a power surge to the existing main transformer with high-voltage cables that have completed the transition. During the power surge of the existing main transformer, the circuit breaker and disconnector are opened and closed in the control room, and no idle personnel are allowed to stay in the high-voltage site;

[0093] The power supply impulse test is carried out twice. The first impulse test lasts for 10 minutes, and the oil temperature and oil level are recorded. After the first impulse test is successful, the high-voltage room busbar is tested to confirm whether there is electricity and check whether there is any abnormality in the equipment;

[0094] The second impulse test will be started 10 minutes after the first impulse test. Before the second impulse test, move the isolating switch on the 27.5KV feeder side to the open position and the circuit breaker to the closed position. After the second impulse test is successful, observe whether the bus voltage on the 27.5KV side is normal. The second impulse test lasts for 5 minutes. After the impulse is completed, restore related equipment.

[0095] S11, the skylight point ends, the existing main transformer that has completed the transition is put into operation, and steps S5-S10 are repeated to transition the next existing main transformer.

Claims

1. A method for transitioning a traction substation transformer from direct power supply to AT power supply in an operating line, characterized in that: The steps include: S1, construction site survey Conduct on-site surveys based on construction drawings to determine the locations of new and existing equipment and make proper markings; S2, Transition door frame and neutral point support installation t1. According to the construction site survey, determine the position of the transition portal frame and the existing neutral point, cast the foundation of the transition portal frame and the existing neutral point in advance, and maintain the foundation to ensure that the foundation bearing capacity meets the requirements; t2, install the transition door frame on the basis of the transition door frame, set up supporting insulators and lightning arrester I on the transition door frame, and install the neutral point bracket on the existing neutral point; S3, existing main transformer transition foundation construction Laying transverse sleepers and longitudinal sleepers at the existing main transformer transition position determined in step S1, and laying steel plates on the transverse sleepers and longitudinal sleepers as the existing main transformer transition foundation; S4, transition cable laying and cable head production t1. According to the on-site investigation and in combination with the construction drawings, determine the number, model specifications, voltage circuit, and control circuit of the transition cable, and lay the transition cable. One end of the transition cable is used to connect the existing main transformer protection panel, and the other end is used to connect the existing main transformer body box and the existing neutral point device operating mechanism box; t2, make the cable head of the transition cable, and do not connect the wires for the time being; S5, removal of existing main transformer soft busbar and equipment leads Select an existing main transformer as the existing main transformer to be transitioned, put the existing main transformer to be transitioned in standby state, and other existing main transformers in operation state. In the skylight point, remove the soft busbar above the existing main transformer to be transitioned and the portal frame crossbeam of the existing main transformer to be transitioned, the high-voltage bushing connection line and the low-voltage bushing connection line of the existing main transformer to be transitioned, the circuit breaker lead-down line corresponding to the existing main transformer to be transitioned, the grounding connection flat steel of the existing main transformer to be transitioned, the return connection flat steel of the existing main transformer to be transitioned, and the existing neutral point device connection flat steel corresponding to the existing main transformer to be transitioned; S6, secondary circuit reverse connection In the skylight point, remove the operating mechanism box of the existing neutral point device corresponding to the existing main transformer to be transitioned, the existing main transformer body box, the existing main transformer outdoor terminal box and the related wiring of the existing main transformer protection panel; S7, the existing main transformer and the corresponding existing neutral point device to be transferred t1, laying the shift track between the existing main transformer to be transferred and the transition foundation of the existing main transformer, and using the electric hydraulic manual shifting method to shift the existing main transformer to be transferred to the transition foundation of the existing main transformer; t2, after the existing main transformer is in place, restore the existing main transformer body box, the existing main transformer outdoor terminal box and the existing main transformer protection panel related wiring, and restore the jumper between the existing main transformer and the circuit breaker after the transition is completed; t3, relocate and install the existing neutral point device, install the operating mechanism box, lightning arrester II, current transformer and disconnector of the existing neutral point device onto the built neutral point bracket, and restore the wiring; S8, High voltage cable laying and wiring Lay high-voltage cables and connect them to the existing low-voltage bushings of the main transformer along the transition portal frame; S9, test of existing main transformer after transition is completed Carry out body test and protection test on the existing main transformer after the transition is completed; S10, the existing main transformer power transmission impact and operation after the transition is completed Apply for a power outage for the entire station within the skylight point, and conduct a power surge to the existing main transformer with high-voltage cables that have completed the transition. During the power surge of the existing main transformer, open and close the circuit breaker and disconnector in the control room; S11, the skylight point ends, the existing main transformer that has completed the transition is put into operation, and steps S5-S10 are repeated to transition the next existing main transformer.

2. According to the method for transitioning the transformer of a traction substation from direct power supply to AT power supply on an operating line as described in claim 1, in step S1, firstly, the insulation distance between the position of the existing main transformer after displacement and the live equipment is ensured, and secondly, the position of the existing main transformer after displacement is ensured not to affect the foundation excavation of the new equipment.

3. According to the method for transitioning the transformer of a traction substation from direct power supply of an operating line to AT power supply of an operating line in step S4, when the transition cables are laid, they do not cross each other, and spare lengths are left at the terminals and the wall bushings; When transition cables enter or exit cable trenches, troughs, or buildings, the entrances and exits shall be sealed with fireproof materials; The bending radius of the transition cable shall not be less than 15 times the diameter of the transition cable.

4. According to the method for transitioning the transformer of a traction substation from direct power supply to AT power supply on the operating line as described in claim 1, in step S6, a multimeter is used to test whether the operating mechanism box of the existing neutral point device, the existing main transformer body box, the existing main transformer outdoor terminal box and the existing main transformer protection disk are energized and records are kept. After confirming that they are not energized, they are removed.

5. According to the method for transitioning a traction substation transformer from direct power supply to AT power supply on an operating line as described in claim 1, in step S8, the high-voltage cable clamp is made of aluminum.

6. According to the method for transitioning the transformer of the traction substation from direct power supply to AT power supply of the operating line according to claim 1, in step S10, the power supply impact test is carried out twice, the first impact test lasts for a preset time, and the oil temperature and oil level are recorded. After the first impact test is successful, the high-voltage room busbar is tested to confirm whether there is electricity and check whether there is any abnormality in the equipment; After the first impact test is completed, the second impact test will start at a preset time interval. Before the second impact test, the feeder side disconnector will be moved to the open position and the circuit breaker will be moved to the closed position. The second impact test will last for a preset time. After the second impact test is successful, observe whether the bus voltage is normal. After the impact is completed, restore related equipment.

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