GWPS-UPS/3kVA Online Double-Conversion UPS

Product Description

The UPS primarily consists of a rectifier with power factor correction (PFC), DC bus, inverter, battery charger, battery system, static bypass and control unit.

• Normal mode: The AC input is converted to DC by the rectifier and then converted back to regulated AC by the inverter. The inverter continuously supplies the load while the battery charger maintains the battery.
• Stored energy mode: When the AC input is unavailable or outside the permissible limits, the battery supplies the inverter through the DC bus. The transfer time from normal mode to stored energy mode is typically 0 ms.
• Bypass mode: If the UPS is overloaded, the inverter fails or another abnormal condition occurs, the load can be supplied through the static bypass, provided that the bypass source is within the permitted transfer limits.
• ECO mode: The load is normally supplied directly from the bypass source to reduce power-conversion losses. Power conditioning and disturbance attenuation are lower than in online double-conversion mode.
• Monitoring: The LCD displays input, output, load, battery, operating mode and alarm information. Optional communication interfaces allow integration into remote monitoring and management systems.

Product Functions

Online Double-Conversion Operation

• The AC–DC–AC topology continuously supplies the load through the inverter in normal mode, providing regulated output voltage and frequency.
• Subject to certification of the selected model, this operating topology may be classified as VFI under IEC 62040-3.

Interruption-Free Transfer to Stored Energy Mode

• If the AC input fails or exceeds the permissible limits, the UPS automatically enters stored energy mode. The transfer time is typically 0 ms, making the UPS suitable for electronic and control equipment that cannot tolerate a momentary loss of power.

Voltage and Frequency Regulation

• The UPS regulates the output voltage and frequency and suppresses the effects of input overvoltage, undervoltage, frequency deviations and other upstream power disturbances on the load.

Static Bypass

• If the UPS is overloaded or the inverter develops a fault, the load can be transferred to the static bypass, provided that the bypass voltage, frequency and phase angle satisfy the specified transfer conditions.

Intelligent Battery Management

• The UPS supports automatic charging, float-charge management, charging-current limitation, battery undervoltage protection and battery-condition monitoring. Extended-runtime models can be connected to external battery packs.

ECO Mode

• In ECO mode, the load is normally supplied directly from the bypass source, allowing overall system efficiency to exceed 95%.
• Because ECO mode bypasses the main double-conversion power path, it generally provides less voltage and frequency regulation and lower attenuation of upstream disturbances than online double-conversion mode.
• In addition, transfer from bypass supply to inverter supply may involve a non-zero transfer time, depending on the UPS topology, synchronization status and control logic. ECO mode should therefore not be enabled by default for critical protection, control or communication loads.

Protection and Alarm Functions

Depending on the selected model, the UPS provides protection and alarms for:

• Input overvoltage and undervoltage;
• Input frequency outside the permissible range;
• Output short circuit;
• Output overload;
• UPS overtemperature;
• Battery undervoltage and overcharge;
• Battery charger failure;
• Inverter failure;
• Static-bypass abnormality;
• Fan or internal system failure.

Local and Remote Monitoring

• The LCD and LED indicators display electrical measurements, operating status and alarm information. Depending on the configuration, the UPS may support USB, RS-232, RS-485, dry-contact and SNMP network interfaces.

Cold Start and Automatic Restart

• The cold-start function allows the UPS to start from the battery when no AC input is available. After the utility supply is restored, the UPS can automatically resume normal operation and recharge the battery, subject to the configured operating logic.

Technical Specifications

Static-Bypass Transfer

• Normal transfer between the inverter and static bypass generally requires the bypass voltage, frequency and phase angle to remain within the UPS synchronization window.
• When these conditions are satisfied, some models provide no-break transfer, while others may have a transfer time of several milliseconds. If the bypass source is not synchronized or is outside the permitted voltage or frequency range, the UPS may inhibit or delay the transfer, perform a non-synchronized transfer, or disconnect the output, depending on its control logic.
• For contactors, AC coils, variable-frequency drives and other phase-sensitive loads, the load hold-up time and transfer tolerance must be verified against the selected UPS.

Overload Capability

• The overload capability and permissible overload duration shall be confirmed using the datasheet and test data for the selected 3 kVA model.
• Overload performance may differ between normal mode, stored energy mode and bypass mode. Values specified for another UPS series or power rating must not be used for product selection.

Backup-Time Considerations

The 3 kVA rating represents the apparent-power capacity of the UPS and does not indicate a fixed backup time. The available backup time depends on:

• Actual active and apparent load power;
• UPS inverter efficiency;
• Battery-string voltage and capacity;
• Battery discharge rate;
• Battery age and condition;
• Ambient temperature;
• End-of-discharge voltage.

UPS and battery selection must therefore consider the continuous load, peak load, load characteristics and required backup time.

High-Inrush and Nonlinear Load Considerations

When supplying AC contactors, electromagnetic coils, AC-operated circuit-breaker mechanisms, variable-frequency drives, motors, pumps, fans, air-conditioning equipment or other inductive, nonlinear or high-inrush loads, the following characteristics must be evaluated:

• Starting current;
• Peak apparent power;
• Load power factor;
• Load crest factor;
• Starting duration;
• UPS overload capability;
• Stored-energy-mode overload capability.

The UPS must not be selected solely according to the load’s rated active power.

In substations, circuit-breaker tripping and closing circuits are normally supplied by a dedicated 110 V DC or 220 V DC station DC system. An AC UPS should only be considered if the circuit-breaker operating mechanism is specifically designed for an AC control supply and its inrush-current requirements have been verified.

5. Applications

• Power systems: Protection relays, bay control units, SCADA workstations, communication gateways, network switches and power-quality monitoring equipment;
• Industrial automation: Programmable logic controllers (PLCs), distributed control systems (DCS), industrial computers, human–machine interfaces (HMIs), control instruments and data-acquisition equipment;
• Communication systems: Communication gateways, routers, fibre-optic communication equipment and small communication cabinets;
• IT equipment: Servers, workstations, network-attached storage (NAS) and edge-computing equipment;
• Renewable-energy facilities: Monitoring, communication and data-acquisition equipment in solar PV plants, wind farms and battery energy storage systems (BESS);
• Security and building systems: Video surveillance, access control, alarm systems and emergency communication equipment;
• Laboratories and testing facilities: Instruments and test equipment requiring continuous, regulated AC power.

This UPS is primarily intended for electronic, communication and control loads. Motors, air-conditioning equipment, high-power variable-frequency drives, energy-regenerative loads and other high-inrush loads require a dedicated load-compatibility and capacity assessment by the UPS manufacturer.