I. UPS Uninterruptible Power Supply - Uninterruptible Power Cutover Process
In power supply cutover, for dual-power supply equipment, a power-off cutover method can be used; however, for single-power supply equipment, especially if the equipment is critical and cutover cannot be interrupted, a power-on cutover process is often required. The cutover process and steps are shown in the following figure:
UPS Uninterruptible Power Supply – Uninterruptible Connection
Suggested steps:
1. A new UPS system has been built, and the system commissioning and battery capacity testing have been completed.
2. Lay temporary cables from the new UPS output panel to the power supply cabinet to be cut and the bypass switch of the old input panel. After confirming that everything is correct, energize the cables.
3. After testing that the power supply is normal, turn off the inverter of the old UPS system and confirm that the old UPS is working in bypass mode. At this time, the power supply of the old UPS system and the power supply of the new UPS system are from the same source (the outputs both come from the new UPS system).
4. Connect the main output of the new UPS, test the voltage at the upper and lower terminals of the main circuit breaker of the main unit, and perform phase verification (measure the voltage difference between the upper and lower terminals of the main side standby switch, which should be less than 1V in principle). After confirmation, the main side standby switch can be closed first to confirm the current, and then the main side main switch can be disconnected.
5. Remove the main cable from the old UPS to the end unit.
6. Using the same method, cut over the backup power supply.
7. Once the splicing is complete, remove the temporary and old cables.
8. Properly mark and label circuit breakers and cables.
Note: Considering the different battery configurations between different UPS systems and the short battery replacement cycle in UPS systems, UPS replacement is generally carried out simultaneously with battery replacement. Therefore, battery cutover steps are generally not considered during UPS cutover.
II. Basic Principles of Cutover
1. Principle of Unimpeded Network Security
Online power system cutover projects must adhere to the principle of ensuring the safe operation of on-network equipment and the smooth operation of the entire network. Any operation that endangers the network security must be terminated unconditionally.
2. Principle of trouble-free equipment
Before and during the implementation of the online power system cutover project, it is essential to ensure that both the new and old equipment are in good working order and free from faults. If any factor that may endanger the safe power supply is detected, the project must be terminated unconditionally and can only continue after the fault has been eliminated.
3. Principle of Low Business Risk
If the power supply cannot be interrupted during the operation, an online uninterrupted power cutover solution should be adopted; otherwise, a power-off cutover solution should be adopted.
Engineering cutovers should be scheduled to avoid peak business hours, with major cutovers to be carried out at night.
The cutover date should avoid major holidays, periods of major communication support missions, and other network adjustments and version upgrades scheduled by other professional departments.
4. Principle of qualified construction personnel
Engineers implementing online power system cutover projects must be proficient in power equipment operation and engineering construction, familiar with communication power system cutover procedures, and have emergency plans memorized.
The construction team that performs the cutover must have a construction certificate with the corresponding engineering level qualification.
5. Principle of full supervision by maintenance departments
During the cutover process, the maintenance department should assign dedicated personnel to supervise the entire process, assist in the design and survey of the cutover project, review the cutover plan and emergency plan, and oversee the implementation of the cutover.
6. The "one-vote veto" principle of the maintenance department.
During the cutover project, the maintenance department has the right to veto the cutover work and terminate the project if any major defects in the design or major construction safety hazards are discovered.
III. UPS Uninterruptible Power Supply Cutover Preparation
1. The new UPS system has completed startup commissioning, full battery capacity testing, and monitoring is in place.
2. Lay cables in advance and affix standard cable labels; when temporary cables are needed, select appropriate wire diameters, ensure reliable connections, and provide clear identification.
3. Based on the wiring positions of the original power equipment cables, assign cable numbers and labels to ensure that the cables are not confused during disassembly and assembly.
4. Confirm that all dual-power devices have their main and backup power modules working properly and that the main and backup power supplies are separate.
5. Issue a cutover project announcement in advance.
6. Confirm that all relevant departments have backed up their data for related business operations and have prepared contingency plans.
7. Firefighting equipment and safety rescue equipment are in place.
8. Wear and use personal protective equipment correctly, do not carry any metal objects, and remove any personal accessories that may cause safety issues (watches, name tags around the neck, etc.).
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