Complete Guide to DEIF GPU-3 Generator Protection Unit

Hardware architecture and slot configuration

The GPU 3 adopts a standard 8-slot backplane structure, and each slot can accommodate different functional cards. Users can flexibly configure according to their ordering options. The following table summarizes the standards and optional functions for each slot:

Slot standard features optional features (option code)

#1 power supply (8-36V DC, 11W), 1 status relay, 5 relay outputs, 2 pulse outputs (kWh/kvarh), 5 digital inputs -

#2-H2 (Modbus RTU), H3 (Profibus DP), H8.2 (External I/O Module CAN), H9.2 (RS-232 Modbus)

#3- M12 (13 x digital input, 4 x relay output)

#4- M14.4 (4 x relay output), E1/E2/EF2/EF4/EF5 (various analog/relay combination GOV/AVR output)

#5 AC measurement (voltage, current, isolation) -

#6-F1 (2 × 0-20mA transmission output), M13.6 (7 × digital input), M14.6 (4 × relay), M15.6 (4 × 4-20mA input)

#7- Engine interface board (optional, including MPU input, multi-purpose input, start/stop relay, CAN communication)

#8-M13.8/M14.8/M15.8/M15.8 (same as # 6 expansion), H8.8 (Beckhoff I/O module CAN)

Key option combination precautions: Options in the same slot are mutually exclusive (e.g. E1 and E2 cannot be selected simultaneously), and some software options depend on hardware (e.g. voltage control D1 requires an analog output board). Engineers should refer to the "Hardware Overview" and option exclusion table provided by DEIF when selecting models to avoid conflicts.

Synchronization, engine control, and display layout

4.1 Synchronous grid connection function (option G2)

After selecting the synchronization function, GPU 3 can detect the voltage difference, frequency difference, and phase angle difference between the generator and the bus, automatically issue a closing command, and exit the regulation after closing, only retaining the protection function. This function is suitable for situations that require parallel or grid connection, without the need for additional synchronization relays.

4.2 Engine Control and Protection (Option Y7 or Y1)

This option requires the installation of an engine interface board (located in slot # 7), which has an independent power input (terminal 98/99, 8-36V DC, 5W) and an independent processor that can independently execute emergency shutdown in the event of a main CPU failure. Onboard resources include:

Magnetic electric speed sensor input (MPU, 0.5-70V AC, 10-10000Hz)

Three sets of multi-purpose inputs (configurable as 0-20mA, Pt100/Pt1000, RMI, 0-40V DC or digital input with wire breakage monitoring)

Multiple digital inputs (remote start/synchronization, remote unload/stop, start permission, operation feedback, etc.)

Relay outputs for startup preparation, starting motor, running coil, shutdown coil, etc. (all with wire breakage detection)

Two redundant CAN interfaces (for internal communication or J1939 engine interface)

This option allows the GPU -3 to function not only as a protector, but also as a complete generator set controller, especially suitable for automated cabins or unmanned power stations.

4.3 Display Layout Options

According to the order, there are three standard layouts for the display interface:

Y5 (GB control): Only displays generator circuit breaker control and measurement, suitable for pure protection applications.

Y7 (Engine Control): Emphasize engine start/stop and operating status.

Y1 (engine+GB control): The most complete interface, providing both engine and circuit breaker operations.

In addition, AOP-1 (16 programmable LEDs+8 buttons) or AOP-2 (with status relay, CAN communication) can be optionally selected for remote control panel, which can connect up to 5 AOP-2.

Communication interface and integration capability

GPU 3 supports multiple communication protocols, making it easy to integrate into upper level monitoring systems (SCADA/PLC):

Modbus RTU (Option H2): Two wire RS-485, capable of connecting to fieldbus networks, transmitting measurement values, alarms, and control commands.

Profibus DP (option H3): Suitable for mainstream PLC systems such as Siemens to achieve high-speed data exchange.

Ethernet TCP/IP (Option N): Supports Modbus TCP/IP, EtherNet/IP, and can send SMS/email alerts for remote operation and maintenance.

CAN bus: Built in two CAN channels (slot # 7 standard), supporting internal multi machine communication (for load distribution between multiple GPUs -3 or PPM -3), and optional H5/H7 for direct communication with engine ECU (J1939, MTU MDEC, etc.).

All communication interfaces are isolated from the measurement circuit to ensure reliability.

Technical parameters and engineering adaptability

6.1 Measurement and Accuracy

Voltage measurement: 100-690V AC (phase to phase), accuracy level 1.0, capable of withstanding 4 times rated continuous and 80 times 1-second overload.

Current measurement: 1A or 5A CT input, power consumption per phase 0.3VA, overload capacity 4 × In continuous, 20 × In for 10 seconds.

Frequency range: 30~70Hz.

Temperature effect: ± 0.2% full-scale/10 ℃.

6.2 Power Supply and Power Consumption

Main power supply (terminal 1/2): 12/24V DC nominal (8-36V DC operation), maximum power consumption of 11W, built-in 10ms power-off hold (drops from 24V to 0V).