The core method to improve the long-term reliability of high frequency on-line UPS
From seven dimensions: design selection, installation and operation, environmental control, load matching, battery management, regular maintenance and redundant architecture, we will give you a set of schemes that can be directly used for project landing:
First, the early selection and configuration (from the source to build reliability)
Deregulation selection
The long-term load rate of UPS should be controlled at 40% ~ 60%, and long-term full load and overload operation is strictly prohibited. Power components are derated to reduce temperature rise and stress aging.
Optimal topology and devices
Choose full-bridge high-frequency online double conversion architecture, brand original IGBT, rectifier inverter module, high-quality electrolytic capacitor/thin film capacitor; Preference is given to devices with wide temperature range and long life.
Standard isolation and protection
Built-in input lightning protection, EMI filtering, output isolation transformer, overvoltage/undervoltage/overcurrent/short circuit/overtemperature/battery low voltage multiple hardware protection.
Second, the installation and wiring specifications
Independent distribution circuit
UPS input and output are separately open, and are not in the same circuit as inductive load and impact load; The cable diameter shall be sufficiently redundant to reduce line loss and heat generation.
Reliable grounding
Strictly ground the working place, protective place and lightning protection place separately and in compliance, and the grounding resistance reaches the standard to avoid interference and surge damage to the control panel.
Strong and weak current separation
UPS power line and monitoring communication line are routed separately to avoid false alarm and bypass caused by electromagnetic interference.
Third, the computer room/operating environment control (high-frequency machines are most afraid of high temperature, dust and humidity)
Temperature control
The ambient temperature is 20 ~ 25℃, and the life of capacitor and battery will be reduced by nearly half for every 10℃ increase. It is forbidden to seal the computer room without heat dissipation.
Dust-proof, moisture-proof and anticorrosion
Install dust screen and clean the filter screen regularly; Moist areas are equipped with dehumidifiers to avoid condensation, creepage and corrosion of circuit boards; Industrial-grade anti-corrosion machine shall be selected for chemical/dust environment.
Ventilation and heat dissipation
Ensure the left and right heat dissipation space before and after UPS, do not block the air inlet and outlet, and the air duct of the cabinet is unobstructed.
Fourth, load side optimization
Isolation impact load
Air-conditioning, elevators, frequency converters, motors and other inductive impact loads are not directly connected with UPS, or are isolated and soft-started, so as to avoid instantaneous surge breakdown of power devices.
Put an end to nonlinear harmonic overload
When nonlinear loads such as servers and switching power supplies are concentrated, high-frequency UPS with harmonic suppression and active filtering is selected to reduce harmonic heating on the rectifier side.
Hierarchical load management
Important core loads give priority to power supply, and non-critical loads can be powered off with delay to reduce the long-term on-load pressure of UPS.
V. Battery system management (80% of UPS failures come from batteries)
Temperature adaptation
The battery environment is also controlled at 20 ~ 25℃, and high temperature is the number one reason for bulging and capacity attenuation of lead-acid batteries.
Accurate setting of equalizing charge/floating charge voltage
According to the manufacturer's standard, set the floating charging and equalizing charging pressures to avoid over-charging, bulging and under-charging.
Periodic capacity check and monomer monitoring
Do battery discharge test regularly, select battery inspection module, monitor cell voltage and internal resistance, and eliminate deteriorated cells in advance.
Avoid shallow charging and shallow discharging and long-term floating and idling.
When the long-term commercial power is normal, small-capacity nuclear discharge is carried out every quarter to prevent the battery from passivation and aging.
Six, daily operation and maintenance and regular maintenance
Daily inspection
Look at the alarm, temperature rise, bypass state, fan operation, and whether there is abnormal sound or smell; Monitor input voltage, frequency, load rate and battery voltage.
Regular dust removal fastening
Stop the machine every year to clean the dust, fasten the power terminals and wiring strips, and prevent loosening, heating and sparking.
Preventive replacement of fan and capacitor
Electrolytic capacitor and cooling fan of high-frequency machine are wearing parts, so they should be replaced preventively according to the life cycle of the manufacturer, and don't wait for the fault to be repaired.
Firmware and logic optimization
Regularly upgrade the original firmware, correct logic bugs, and optimize the logic of voltage stabilization, switching and alarm.
VII. Architecture Redundancy Design (highest level of reliability)
Dual-machine hot backup (1+1 redundancy)
Two high-frequency UPS are connected in parallel and redundant, and the single fault automatically switches without interrupting the load power supply.
Bypass redundancy
Manual maintenance bypass and automatic bypass are configured, and power is not interrupted during maintenance to avoid the risk of maintenance downtime.
Remote monitoring and alarm
Access to dynamic ring monitoring, SMS/WeChat/pop-up alarm, and discover hidden dangers such as overheating, battery deterioration and abnormal input in advance.
Eight, the use of operating habits
Frequent start-stop and frequent manual switching of inverter/bypass are strictly prohibited; Avoid long-term forced loading of low-voltage and high-voltage commercial power, and timely pre-stabilize or adapt to transformation when the commercial power is abnormal.
