DEIF LSU-112DG generator set parallel control unit

2.3 Self monitoring function

The LSU-112DG is equipped with a built-in microcontroller and a self-monitoring circuit. The green "POWER" LED is constantly on, indicating that the power supply is normal and the program is running correctly; If the LED flashes at 2-3Hz, it indicates that although the power supply is normal, the program is running abnormally, and the status output terminal (17-18) will be disconnected (fault indication). This design greatly facilitates on-site troubleshooting.

Detailed explanation of core functions

3.1 Speed Control Output (SG ▲/SG ▼)

LSU-112DG provides two relay contact outputs, which are respectively used to control the "speed increase" and "speed decrease" of speed regulating motors or actuators. The controller adopts a P controller (proportional control) internally, which generates pulse width modulation signals based on frequency/power deviation. The key parameters include:

T-N (minimum on-time): Within the proportional band, the minimum duration of the control pulse can be adjusted within a range of 25~500ms.

X_P (Proportional Band): Set a deviation range within which the pulse duty cycle is proportional to the deviation. For frequency control, the proportional band is 0~± 2.5Hz; for power control, it is 0~± 50% of the rated power.

T-P (cycle time): The time interval between the starting points of two adjacent pulses, usually 10 times the T-N, but can also be selected as 5, 15, or 20 times the T-N through jumper wires.

Deadband: Set a deviation zone that does not generate adjustment pulses to avoid frequent actions of the governor. The default power dead zone is ± 2%, and the default frequency dead zone is ± 0.1Hz, both of which can be adjusted through jumper wires.

When using a DC servo motor, it must be driven by an external intermediate relay and a transient suppressor must be connected in parallel to the relay coil to protect the contacts.

3.2 Unload Input

Terminals 33-34 can be connected to a passive normally open contact. When the contact is closed, LSU-112DG will control the unit to reduce load to zero power and automatically disconnect its power output (PS line) from the bus. This function is commonly used for preparation before unit disconnection or quick unloading in emergency situations.

3.3 Reference Input (Ref.) and Local Power Control

Terminal 35 is a reference input terminal used for fixed power control mode (such as the unit delivering constant power to the grid). The input signal is+0.5V to+5V DC (for terminal 36 "⊥"), corresponding to 10% to 100% of the rated power. This input is activated at 0.55V and deactivated at 0.45V. When this input is valid, LSU-112DG is still connected to the PS and FS lines, but the PS line only serves as an output (broadcasting the actual power of the machine to other units) and does not participate in the comparison. This means that the local machine no longer responds to load distribution, but instead sets a fixed output power while still participating in frequency synchronization.

Terminal 37 provides a+5V reference voltage output, which can be used to connect an external potentiometer to form a local power setting circuit.

3.4 Derating setting

The front panel of LSU-112DG is equipped with a derating potentiometer, which can adjust the corresponding generator capacity within the range of 50% to 100% (such as derating a 150kW unit to 100kW). After the reduction, load distribution will be based on the reduced capacity. For example, if a 100kW unit is connected in parallel with a 150kW unit that has been downgraded to 100kW, the total load of 125kW will be evenly distributed as 62.5kW+62.5kW. If the capacity is not reduced, it will be allocated as 50kW+75kW according to the actual capacity ratio. The derating function provides great flexibility for mixing different capacity units.

3.5 External frequency and power transmitter

If higher precision is required or to cope with unbalanced loads, LSU-112DG supports external transmitters:

External power input (terminals 31+, 32-): Connect 4-20mA DC signal, corresponding to 0-100% power. Recommend using DEIF TAS-331DG.

External frequency input (not clearly indicated, but the document mentions that external frequency transmitters can be shared): Please refer to the application notes.

When an external power transmitter is connected, the built-in I × cos φ transmitter is automatically disabled.

Wiring and Configuration Guide

4.1 Overview of Terminal Functions

Terminal identification function description

1.3 X1/X2 auxiliary power input (AC or DC, depending on the model)

17,18 Sta status output (normally open contacts, closed during normal operation)

28,29 IL1 current transformer input (S1 connected to 28, S2 connected to 29)

31,32 Ext. P external power transmitter input (31+, 32-), short circuit when not in use

33,34 Uni load shedding input (connected to passive normally open contacts)

35 Ref. Reference input (0.5-5V corresponds to 10-100% power)

36 ⊥ public area (internally connected to all ⊥ terminals)

37+5V reference voltage output (for local potentiometer)

38,39 FS, ⊥ frequency sharing line and common terminal