DEIF LSU-112DG generator set parallel control unit

DEIF LSU-112DG generator set parallel control unit

In distributed power generation, backup power sources, and grid connected power stations, parallel operation of multiple generator units is the key to achieving capacity expansion, improving power supply reliability, and operating economy. However, to achieve stable parallel connection of multiple units, precise load distribution and frequency synchronization control capabilities are necessary. The LSU-112DG launched by DEIF company is a dedicated control unit designed for this purpose. It can accurately regulate the speed of the generator set's prime mover (diesel engine, gas engine, etc.), ensuring that the unit can stably and reasonably share the load when running alone, parallel with the power grid, or parallel with other units. This article provides a comprehensive analysis of the working principle, functional characteristics, technical parameters, and application configuration of LSU-112DG based on official technical materials.

Product Overview and Application Scenarios

LSU-112DG is a generator set prime mover control unit, mainly used to control the prime mover in the generator set (such as diesel engines, gas engines, etc.). Its core task is to adjust the speed of the prime mover according to the grid frequency or power command, thereby controlling the output power and frequency of the generator.

This unit can be applied to the following four main operating modes:

Isolation single machine mode: As an independent power source, LSU-112DG controls the prime mover to maintain a stable frequency (such as 50Hz or 60Hz), supplying power to isolated loads.

Parallel connection mode with the power grid: When the generator unit needs to operate in parallel with the infinite power grid, LSU-112DG can control the unit to deliver the set power to the power grid (constant power control). At this time, the power grid frequency is determined by the large grid, and the unit only needs to adjust the active output.

Multi machine parallel islanding mode: When multiple generator units jointly form an isolated power grid, LSU-112DG achieves real-time frequency and power sharing between units through parallel lines, ensuring load distribution according to unit capacity ratio.

Frequency and power combination control: In certain special applications, coordinated control of frequency and power can be achieved simultaneously.

The LSU-112DG is designed to directly drive the actuator of mechanical speed controllers (by outputting acceleration/deceleration pulses through relay contacts), and can also be used in conjunction with DEIF's electronic potentiometers (such as EPN-110DN or EPQ-96) to control electronic speed controllers, covering a wide range of applications from traditional mechanical speed controllers to modern electronic speed controllers.

Working principle and core measurement

2.1 Measurement principle

The LSU-112DG integrates a frequency transmitter and a power transmitter internally. It calculates the current frequency and power by collecting voltage (single-phase or two-phase) and current (single-phase) signals from the generator.

Frequency measurement: taken from voltage signals, with high accuracy and fast response. If the system requires higher frequency stability, an external common frequency transmitter can be connected to provide a unified frequency reference for all parallel LSU-112DGs, achieving more accurate synchronization.

Power measurement: The built-in power transmitter is based on the I × cos φ principle, which calculates active power by measuring current and power factor angle. This transmitter is suitable for three-phase systems with balanced loads, and the wiring method is 1W3 (two watt meter method, used for three-phase three wire balanced loads) or 1W (single-phase method, used for phase voltage and neutral point). For applications that may experience severe unbalanced loads, it is recommended to connect an external power transmitter such as TAS-331DG recommended by DEIF (outputting 4-20 mA). At this time, the built-in transmitter will automatically disconnect and the external signal will prevail.

2.2 Parallel tracks (PS and FS)

The core parallel mechanism of LSU-112DG relies on two analog parallel lines:

FS line (frequency sharing line): All LSU-112DGs of parallel units output their measured frequency signals (converted into voltage) to the common FS line. The voltage on this line reflects the average frequency of the system. Each unit compares its frequency with the FS line voltage to generate a frequency deviation signal, which is used to adjust the speed and make the frequencies of all units tend to be consistent.

PS line (power sharing line): Each unit outputs its power signal (converted into voltage) to the common PS line. The voltage on the PS line represents the average value of the total load (proportionally). Each unit compares its actual power with the PS line voltage to generate a power deviation signal, which is used to adjust the throttle and distribute the load according to the set ratio.

These two lines are both analog buses (-5V to+5V), corresponding to a frequency offset of ± 2.5Hz or a power of 0-100%. When the unit is disconnected from the bus or the auxiliary power supply loses power, the built-in relay will automatically disconnect its output to avoid interference with the bus.