Guide Specification –
5.2.3Battery Protection
The converter shall be provided with monitoring and control circuits to protect the battery system from damage due to excessive discharge. Converter shutdown shall be initiated when the battery voltage reaches a discharge cutoff voltage of 400 VDC. Automatic shutdown based on discharge time is not acceptable.
5.2.4DC Ripple
AC Ripple on the DC Bus shall be less than 0.2%.
AC Ripple on the Battery charging circuit shall be less than 0.23% for the 80/100/160 kVA UPS, and less than 0.29% for the 225 kVA UPS.
5.3IGBT Inverter:
5.3.1General
The inverter shall be composed of
The inverter shall be capable of providing rated output while operating at any battery voltage within the battery operating range. When the DC battery voltage reaches the operational low voltage limit during a loss of utility AC power, the inverter shall automatically shut off.
5.3.2Output Voltage
The Inverter output voltage shall not deviate by more than +/- 1.0% RMS under the following steady state conditions as the Inverter DC input varies from maximum to minimum:
0% to 100%Unbalanced load
0% to 100%Balanced load
5.3.3Synchronization
The Inverter output voltage shall be automatically synchronized with the bypass AC source as long as the source is within the tolerable frequency and voltage range. If the bypass AC source is not within the range, the control circuitry will stop synchronization and operate the inverter in free running mode. When the bypass AC source recovers to within tolerance, the inverter shall change its frequency (slew rate 1Hz/sec) and track the bypass AC source until synchronization is achieved without causing any disturbance to the load.
5.3.4Output Control
The Inverter can be manually started and stopped using the LCD touch screen controls.
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