In the petrochemical industry, the stable operation of power distribution equipment is directly related to production safety and compliance with environmental standards. The 44 sets of low-voltage switchgear in the sulfur recovery system of Sinopec Guangzhou Company have been in loyal service for 19 years. As customized products delivered by Shanghai LanJian in 2006, these switchgears are now facing operational risks due to aging issues such as overheating of branch busbars and deformation of drawer switchgear pins, despite withstanding nearly two decades of operation. To ensure the continuous and reliable operation of environmental governance equipment, LanJian has customized a targeted in-depth maintenance plan to breathe new life into these aging devices.

I. Targeting the Pain Points: "Health Hazards" of 19-Year-Old Equipment

This set of LMNS series low-voltage switchgear, paired with 11 ABB air circuit breakers, has long undertaken the core task of power distribution for the sulfur recovery system. With the increase of service life, the equipment has gradually exposed a series of problems:

• Overheating of branch busbars has caused sheath burnout, posing a short-circuit risk;

• Secondary pins of some drawer switchgears have deformed and their shells have cracked, affecting contact stability;

• The performance of circuit breakers and components has naturally degraded, leading to a rise in failure probability;

• Environmental governance equipment has extremely high requirements for power supply continuity, and unplanned power outages will result in significant losses.

After on-site investigation, LanJian's technical team accurately identified the core needs: to completely eliminate potential hazards, minimize the impact on production, and extend the service life of the equipment simultaneously.

II. Professional Maintenance: Three Steps to Restore Aging Equipment to "Full Capacity"

Based on the current condition of the equipment, LanJian formulated a full-process in-depth maintenance plan of "Diagnosis - Repair - Optimization", focusing on three core modules:

1.Comprehensive Inspection of Air Circuit Breakers

Conducted full-range maintenance on 11 sets of SACE E3N 32 air circuit breakers: from dust and rust removal, lubrication of rotating parts, to closing contact resistance testing and insulation performance detection, troubleshooted problems such as metal oxidation, loose wiring, and arc extinguishing chamber damage one by one.

2.In-depth Revitalization of Switchgear Cabinets

Covered all types of cabinets including incoming line cabinets, bus tie cabinets, and feeder cabinets: inspected the torque of primary/secondary busbar connection bolts, tightened secondary terminals, repaired fire isolation measures, and measured loop insulation resistance. Implemented special treatment for overheated busbars to eliminate discharge hazards.

3.Precision Repair of Drawer Units

Focused on solving problems such as pin deformation and poor contact of contacts: overhauled mechanical action mechanisms, replaced damaged sockets, tested the pressure of moving contact compression springs, ensuring smooth push-pull operation and reliable contact of drawers. Conducted a comprehensive inspection of hundreds of drawer circuits in 32 feeder cabinets without leaving any blind spots.

III. LanJian's Commitment: Beyond "Repair", Focusing on "Stability"

1.Zero Safety Risk

Implemented strict management procedures: processed electrical work permits, set up construction isolation zones, implemented energy isolation measures, and assigned dedicated personnel for on-site supervision throughout the process to prevent accidental entry into live compartments. Construction staff received specialized safety training and strictly complied with Sinopec Guangzhou's 5S management standards.

2.Well-prepared Emergency Plans

Prepared standby drawer modules. In case of sudden failures, power supply can be restored within 10-20 minutes to ensure production continuity.

3.Comprehensive Service Coverage

Provided a 12-month quality warranty period after maintenance, with professional engineers offering 24-hour free emergency response and free technical training. Submitted a complete report including test data, current condition assessment, and rectification suggestions, allowing customers to have a clear understanding of the equipment status at a glance.

IV. Customer Benefits: Extending the Service Life of Aging Equipment by Another 10 Years is Not a Dream

After in-depth maintenance, this set of 19-year-old low-voltage switchgear has achieved three major improvements:

• Potential hazards have been completely eliminated, failure rate has been significantly reduced, avoiding losses caused by unplanned power outages;

• Equipment performance has been restored to the optimal state, and service life has been extended by 10%-20%;

• Operation and maintenance costs have been significantly reduced, eliminating the need for overall equipment replacement and maximizing cost-effectiveness.

From the equipment delivery in 2006 to the in-depth maintenance in 2025, the cooperation between LanJian and Sinopec has spanned nearly two decades. This is not only a test of product quality, but also a vivid embodiment of LanJian's tenet of "Quality First, Customer Satisfaction". Whether it is customized new equipment or maintenance of aging equipment, LanJian always relies on professional technology and thoughtful service to guard the stable operation of every power distribution system.

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