GWPR200-RP Reverse Power Protection Relay

Product Description

• The GoWatron GWPR200-RP Reverse Power Protection Relay is mainly suitable for reverse power monitoring in 11 kV and 0.4 kV systems. It also provides tripping and closing control for distributed inverters and grid-connection circuit-breakers to prevent reverse power flow. The relay can simultaneously control multiple inverters or grid-connection circuit-breakers to meet the following two requirements. First, the power utility must ensure the quality and reliability of the user’s power supply while allowing renewable energy generation to operate normally, realise its economic benefits and demonstrate the value of clean energy. Second, renewable energy generation must not compromise power-system security or export power to the public utility grid through a power transformer or high-voltage incoming feeder. At the same time, renewable energy should be used efficiently to reduce the user’s electricity costs.
• Human–machine interface: A large Chinese-language LCD displays voltage, current, power, frequency and other electrical quantities in real time. It allows the complete sequence of protection operations to be reviewed and provides a clear, user-friendly operating menu.
• Flexible and independent output configuration: All relay output channels are independent. Protection trips, fault signals and alarm signals can be freely assigned. The eight potential-free outputs are programmable and can be configured to provide four reverse-power trip outputs and four closing-command outputs.
• Flexible installation: The relay supports centralised panel installation and direct installation in switchgear, accommodating different cabinet arrangements at PV project sites.
• High operational reliability: The relay incorporates a comprehensive self-supervision system and can store multiple types of event records. It provides excellent electromagnetic compatibility and is suitable for complex industrial electromagnetic environments.
• Comprehensive expansion interfaces: The relay provides communication and time-synchronisation interfaces and can be seamlessly integrated into a power plant automation and monitoring system.

Product Functions

Protection and Control Functions with Applicable ANSI Codes

• (ANSI 32) Reverse power protection (trip, supporting four trip outputs): When reverse active power exceeds the configured setting, the relay trips the grid-connection circuit-breaker after the configured time delay. The function provides Stage I, Stage II, Stage III and Stage IV definite-time logic and supports four configurable trip outputs.
• Automatic closing when forward power is restored (supporting four closing outputs): After a reverse-power trip, the relay automatically issues a closing command to restore grid-connected operation when forward power returns to the configured value, the specified time delay has elapsed and no closing-blocking signal is present. The function supports four closing outputs.
• (ANSI 59) Overvoltage protection (alarm): The relay continuously monitors the three-phase line-to-line voltages. When the voltage exceeds the protection setting for the specified time delay, an alarm signal is issued.
• (ANSI 27) Undervoltage protection (alarm): When the three-phase voltage falls below the protection setting and remains below it for the specified time delay, an alarm signal is issued. When a VT circuit failure occurs, the undervoltage protection logic is automatically blocked to prevent an incorrect alarm.
• VT circuit failure supervision (alarm): The relay detects abnormalities in the voltage-transformer circuit. When the VT circuit failure criteria and time-delay condition are satisfied, an alarm signal is issued to indicate a fault in the voltage circuit.
• Note: The relay’s built-in logic supports three channels. Through output-bit configuration, it can provide four reverse-power trip outputs and four closing-command outputs.

Measurement and Control Functions

• Analogue measurements: Phase-to-neutral voltages Ua, Ub and Uc; phase-to-phase voltages Uab, Ubc and Uca; phase currents Ia, Ib and Ic; active power P; reactive power Q; power factor cos φ; frequency f; and four-quadrant energy metering EP+, EP−, EQ+ and EQ−.
• Binary inputs and outputs: 14 binary inputs for status acquisition and eight programmable potential-free relay outputs, configurable to provide four trip outputs and four closing outputs.
• Sequence-of-events recording provides accurate time-stamped records of switch status changes.

Event Storage and Recording

• The relay stores 128 protection event records, 128 alarm event records, 128 binary input change records and 128 operation records, as well as 16 self-supervision event records. Each record includes the event time, operating value and event name, facilitating fault tracing and analysis.

Technical Specifications

Applications

• Distributed photovoltaic power plants: The relay is suitable for residential, commercial and industrial small-scale PV grid-connection cabinets. It prevents power from being exported to the utility grid and trips the grid-connection circuit-breaker when reverse power occurs. When PV output returns to normal, the relay automatically closes the grid-connection circuit-breaker. It supports multi-feeder applications requiring four trip outputs and four closing outputs.
• In-plant distributed generation systems: The relay is suitable for internal PV systems, small waste-heat power generation systems and other distributed generation grid-connection points. It prevents reverse power export to the utility grid and meets the requirements for preventing reverse power flow in 11 kV and 0.4 kV systems.
• Local switchgear applications: The relay can be installed directly in a PV grid-connection switchgear panel or centrally installed in a protection panel within a distribution room.
• Automation monitoring systems: The relay can be connected to a substation or distribution-room monitoring system through RS-485 or Ethernet. It transmits protection information, measurements and status signals, enabling remote monitoring and event tracing.