I. Analisis Operasyonal
1.1 Kahangganan sa Operasyon
Ang mga high-voltage disconnect switch giklasiha isip outdoor ug indoor basehan sa lugar sa pag-install, ug isip three-pole o single-pole basehan sa kantidad sa poles. Sa panahon sa operasyon, ang atensyon kinahanglan mas maayo nga ipasabot sa operating current ug voltage sa switch.
Kon ang operating voltage adunay lisod sa rated value, mahimong mag-occur og discharge sa loob sa porcelain insulator. Ang degree sa pag-init mas maayo nga related sa operating current ug naghimo og dako nga impact kon ang external structure magdeform. Ang field operating regulations nag-rehistro nga ang operating temperature sa disconnect switches kinahanglan kontrolhon sa 70°C. Tungod kay wala gi-install ang dedicated arc-extinguishing devices, ang application sa disconnect switches natural nga limitado. Apan, mahimo sila gamiton sa sumala nga mga scenario:
Connecting o disconnecting fault-free lightning arresters ug voltage transformers
Connecting o disconnecting busbar currents sa 220kV o below, pinaagi sa approval gikan sa equipment management department;
Opening o closing ang neutral grounding switch sa fault-free transformer;
Opening o closing ang unloaded lead wires nga may current below 5A, ug controlling ang magnetizing current sa switching operations below 2A para sa unloaded transformers;
Opening o closing ang busbar loop currents, subject sa approval gikan sa equipment management authority;
Opening o closing ang equipotential loop currents sa 220kV o below. Apan, ang mga measures kinahanglan implementar aron maprevent ang accidental tripping sa circuit breakers sa loob sa loop.
1.2 Precautions During Operation
Never operate the isolator under load (i.e., do not energize while switching);
Prevent closing the grounding switch into a live circuit;
Strictly prohibit switching fault currents or operating under load conditions.
Kon ang disconnect switch malihok sa sayop sa ilaha, ang operator kinahanglan agad na reverse ang direksyon sa action aron maputli ang arc kaagad ug maprevent ang further arcing. Bago mo-operate ang disconnect switch, siguraduhon nga ang associated circuit breaker control power engaged. Ang switching operations mahimo lang matuman kon ang circuit breaker open, ang grounding switch disconnected, ang grounding wires removed, ug ang breaker sa open position.
Sa panahon sa energizing, close first ang busbar-side isolator, then ang load-side isolator. Sa panahon sa de-energizing, reverse ang sequence. Aron maprotektahan ang personnel, preferido ang remote operation. Kon ang remote electric control mibuto, local electric operation dapat gihapon. Kon parehas mibuto, manual operation mahimo lang human sa pagsunod sa unlocking procedure ug obtaining proper authorization.
Sa panahon sa operasyon, monitor ang sound sa traditional mechanism alang sa abnormalities ug confirm kon ang full stroke natuman. Padayon nga atento kon ang tanan nga tatlo ka phase mag-operate synchronously ug accurately verify ang ilang final positions.
Sa panahon sa manual operation sa disconnect switch, wear insulated gloves. Sa rainy weather, gamit ang insulated rods nga may rain shields ug wear insulated boots. Ang manual operation dapat swift, apan ang excessive impact dapat iwasan near sa end sa stroke. Human sa closing, inspect ang contact surface alang sa integrity. Sa panahon sa manual opening, rapidly accelerate ang arc extinction human sa blade separates sa contact. Human sa opening, check ang separation angle aron sigurado nga okay sa specifications.
II. Maintenance Strategies
Ang disconnect switch primarily consists of the following components: transmission mechanism, insulation section, support base, operating mechanism, ug conductive parts. Ang operating mechanisms giklasiha isip power-driven ug manual types. Ang Power-driven mechanisms includes pneumatic, hydraulic, ug electric types. Ang maintenance sa disconnect switches kinahanglan address both primary ug secondary systems. Specific maintenance procedures as follows:
2.1 Primary System Maintenance
First, inspect the external appearance:
Check whether the knife switch joints make tight and good contact;
Assess for severe burning or bending;
After opening the switch, use a telescope to observe contacts for oxidation, discoloration, deformation, or burn marks;
Check if porcelain insulators are clean and free from cracking, corona discharge, or audible discharges;
Inspect flange grounding for cracks;
Examine screws for rust or looseness;
Verify proper positioning of the grounding switch;
Confirm secure connection of grounding down conductors;
Ensure mechanical interlocks are intact;
Check transmission mechanisms for bending;
Inspect components for rust, loosening, or detachment.
Lubricate the transmission mechanism regularly and apply industrial-grade grease to friction points periodically.
Second, closely monitor operating current and voltage. During peak load periods, measure temperature to ensure it remains within acceptable limits.
Third, perform special inspections under abnormal conditions:
In extreme weather such as typhoons, check for loose connections, broken strands, poor contact, or strand scattering at terminal joints;
Look for foreign objects on the switch;
In rainy or foggy conditions, inspect porcelain insulators for flashover, discharge, or corona;
After a fault trip, check the switch position and look for signs of overheating at contacts, component deformation, or overheated terminal joints.
2.2 Secondary System Maintenance
When maintaining the secondary system:
First, verify the correctness of secondary wiring diagrams and confirm compliance with design requirements. Check for missing components, design flaws, or unimplemented local modifications. Assess whether motor protection and interlocking functions are necessary.
Second, conduct an on-site verification against the drawings. Record and report any discrepancies. These two steps are fundamental and critical.
Third, perform maintenance per standards:
Confirm that the "five-prevention" (5P) interlock system is properly implemented;
Ensure the control power and motor power for the isolator remain disconnected during operation;
Maintain appropriate voltage levels;
Ensure reliable contact for terminals, especially frequently used ones;
Inspect fuses and circuit protection devices for integrity;
Check the functionality of open/close buttons and switches.
Any issues identified during maintenance should be addressed immediately if possible; otherwise, record them for future resolution. Operators must follow established procedures to perform regular inspections, dynamic maintenance, and condition monitoring to predict equipment status and enable scientific, proactive maintenance.
Additionally, enhance technical training for maintenance personnel to develop multi-skilled expertise, ensuring timely detection and resolution of potential defects, thereby reducing unplanned outages. Invest in technological research—such as applying new materials or automated live cleaning of porcelain insulators—to further reduce the likelihood of switch failures.
III. Conclusion
Ang mga disconnect switch commonly seen sa power system operations. Although their structure is relatively simple, their operational performance and maintenance practices involve considerable expertise. Any failure in a disconnect switch can significantly impact the stable operation of the entire power system. Therefore, it is essential to establish favorable operating conditions based on actual site conditions, implement scientific and rational maintenance strategies, and lay a solid foundation for maximizing the functional reliability of these critical devices.
