High-voltage disconnectors are crucial devices in power systems, used to isolate power, disconnect circuits (under no-load conditions), and perform switching operations. Their operational status is directly related to the safety of the power grid. The following describes common abnormalities associated with high-voltage disconnectors, their causes, and appropriate treatments.
Summary table of common abnormal phenomena and treatment measures
| Abnormal phenomenon | Possible cause | Solution |
|---|---|---|
| 1. Fever, high temperature (most common) | 1. Poor contact, oxidation, or burnt contacts. 2. Insufficient contact pressure or spring failure. 3. Loose conductive circuit connection components (such as terminal blocks or bolts). 4. Prolonged overload operation. |
1. Immediately report to the dispatcher for load transfer or power outage. 2. Use an infrared thermometer to monitor hotspots and record their temperature and trend. 3. After the power outage, inspect and clean the contact surfaces, and replace any severely corroded contacts. 4. Inspect and adjust contact pressure, and replace any failed springs. 5. Tighten all bolts on all conductive connections. |
| 2. The operation is stuck, refuses to move, or does not open or close properly | 1. The transmission mechanism is corroded or stuck. 2. The connecting rod joint pin is loose or broken. 3. The electric operating mechanism motor is faulty or there is a problem with the control circuit. 4. The mechanism is frozen due to severe weather such as freezing. 5. The switch blade and the static contact are not aligned, causing mechanical collision. |
1. Stop operation immediately! Investigate the cause to prevent damage to the mechanism caused by forced operation. 2. Try manual operation. If it works, the problem lies with the motorized mechanism. If it also sticks, the problem lies with the mechanical transmission. 3. Inspect transmission components, remove rust, lubricate, and replace damaged pins and connecting rods. 4. Inspect the motor, contactor, limit switch, secondary circuit, etc. to eliminate electrical faults. 5. Adjust the relative position of the switch blade and the static contact to ensure center alignment. |
| 3. Insulator abnormality | 1. The insulator surface is severely contaminated, causing flashover in a humid environment. 2. The insulator is cracked or damaged. 3. The insulator's adhesive bonding is loose. |
1. Report the problem immediately and request a power outage. 2. Clean or flush contaminated insulators with live water. 3. Replace cracked or damaged insulators; this is a serious defect and requires immediate attention. 4. Inspect and address any loose parts. |
| 4. Automatic opening (self-disconnection) | 1. The anti-incorrect locking device (such as a mechanical locking pin) is inoperative or not in place. 2. The positioning spring or latch of the operating mechanism is inoperative. 3. The device is subject to severe vibration or external impact. |
1. This is an emergency! It could cause an on-load trip and arc short circuit. Report immediately to the dispatcher and check the operation of the relevant line protection. 2. After the power outage, thoroughly inspect the anti-error locking device and the positioning components of the operating mechanism, and repair or replace them. 3. Strengthen daily inspections to ensure the reliability of the locking device. |
| 5. Post insulator shaking | 1. Loose foundation bolts. 2. Loose mounting on the post insulator flange. 3. Excessive impact force during operation. |
1. Tighten the foundation bolts after a power outage. 2. Replace any loose support insulators. 3. Check the operating mechanism and adjust the buffer device to reduce the impact of opening and closing. |
| 6. There is an abnormal sound (discharge sound) | 1. Poor contact leading to tip discharge. 2. Internal breakdown of the insulator or surface creepage. 3. Loose components vibrating under electromagnetic forces. |
1. Combine infrared temperature measurement to determine if there is a discharge at the contact point. 2. Conduct a nighttime inspection with the lights off to observe for sparks. 3. Report the situation and request a power outage to inspect the condition of fasteners and insulators. |
Handling Principles and Safety Precautions
Safety First: All inspections and handling of disconnectors must strictly comply with the "Electric Power Safety Work Regulations."
Prompt Reporting: Any abnormalities, especially severe overheating, insulator damage, or automatic tripping, must be reported immediately to the dispatcher and superiors. Unauthorized handling is prohibited.
Power Outage Handling: Most substantive handling (such as contact grinding and component replacement) requires a power outage, electrical testing, and grounding before proceeding.
Cause Analysis: Before handling, carefully analyze the cause of the abnormality to avoid treating the symptoms without addressing the root cause. For example, if an operator is stuck, do not simply apply force; the root cause must be identified.
Prevention First: Strengthening routine inspections, maintenance, and preventive testing is key to preventing abnormalities.
Preventive Maintenance Recommendations
Routine Inspections:
Visual Inspection: Check insulators for cleanliness and cracks, examine contacts for burn marks, verify integrity of mechanical components, and assess fastenings for looseness.
Infrared Temperature Measurement: Periodically (particularly during high-temperature and high-load seasons) employ an infrared thermography camera to measure temperatures at conductive points of disconnectors. Establish temperature measurement records to promptly identify latent overheating defects.
Acoustic Monitoring: During operation and switching, listen for abnormal discharge noises or vibration sounds.
Routine Maintenance:
Operating Mechanism: Periodically apply suitable grease to transmission and rotating components to maintain mechanism flexibility.
Conductive Circuit: During scheduled power outages, inspect and tighten all conductive connection bolts, measuring circuit resistance.
Contact Cleaning: Regularly inspect main contacts, remove oxidation layers, and apply conductive paste (where applicable).
Insulators: Regularly clean, assess contamination levels, and apply anti-pollution coating (RTV) or undertake modifications as necessary.
Operating Procedures:
Strictly adhere to operating regulations. Ensure decisive and complete closing/opening operations, avoiding delayed or incomplete movements.
After operation, always verify the actual position of the isolator switch, confirming synchronisation and full engagement of all three phases.
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