Basler DECS-100 Digital Excitation System Debugging Guide

Basler DECS-100 Digital Excitation Control System: A Complete Guide to Principles, Applications, and Field Debugging

Product Overview and Application Positioning

The DECS-100 Digital Excitation Control System launched by Basler Electric is a solid-state excitation regulation device designed based on microprocessors, specifically designed for excitation control of brushless AC generators. This device achieves precise control of the output voltage of the generator by adjusting the current of the excitation field of the generator. DECS-100 is encapsulated with epoxy resin and designed for installation behind panels, occupying minimal space in the generator junction box. Its compact and sturdy structure makes it particularly suitable for power generation applications that require strict space and reliability.

DECS-100 supports two excitation power supply modes - permanent magnet generator (PMG) power supply and self parallel excitation (taking power from the generator output), covering various application needs from small and medium-sized diesel generator sets to large industrial power generation facilities. The four quadrant control mode (AVR, FCR, PF, VAR) combined with programmable PID stabilization parameters enables the device to adapt to generators with different excitation system time constants and achieve precise adjustment of reactive power and power factor during grid connected operation.

Compared with large rack mounted excitation systems, the core advantages of DECS-100 lie in its highly integrated compact design (weighing only 1.1kg) and its adaptability to harsh environments with epoxy encapsulation - operating temperature range of -40 to+70 ℃, and passing MIL-STD-810E salt spray testing, making it an ideal choice for harsh working conditions such as ships, oil platforms, and remote power stations.

Core technical specifications

2.1 Control mode and adjustment accuracy

DECS-100 provides four control modes, which can be controlled through BESTCOMS ™ Software configuration:

AVR mode (automatic voltage regulation): The regulation accuracy is ± 0.25% (under rated power factor and constant frequency conditions); When using three-phase induction and 40% total harmonic distortion caused by six SCR loads, the accuracy still remains within ± 0.5%; The temperature drift is ± 0.5%/40 ℃; The response time is less than 1 cycle. The V/Hz slope can be adjusted from 0 to 3PU (0.01PU step), and the inflection point frequency can be adjusted from 40 to 65Hz.

FCR mode (manual/magnetic field current regulation): The regulation range is 0~7Adc (0.01A step), used for backup control or open-loop regulation of excitation current during the debugging phase when AVR mode fails.

VAR mode (reactive power regulation, optional): The regulation range is -100% absorption to+100% output, with 1% step, suitable for maintaining constant reactive power when operating in parallel with an infinite bus.

PF mode (power factor adjustment, optional): The adjustment range is 0.6 lag to 0.6 lead, 0.001 step, suitable for maintaining a constant power factor when parallel with the grid.

2.2 Field output and excitation power supply

Continuous rated output: 63Vdc/7Adc (minimum field resistance 9 Ω)

10 second strong excitation capability: 135Vdc/15ADC (suitable for 5 Ω field resistance) or 90Vdc/10ADC (9 Ω field resistance)

Input power supply: 88~250Vac, 50~400Hz (single-phase or three-phase), from PMG, generator output (self parallel excitation) or auxiliary winding

2.3 Inductive input and measurement accuracy

Generator voltage induction: three-phase or single-phase (terminals E1/E2/E3), maximum 600Vac, PT ratio 1-150 can be set

Bus voltage induction: single-phase (terminal B1/B3, only voltage matching optional model), variable ratio 1-150 can be set

B-phase current induction: 1A or 5A CT secondary optional (terminals CT1/CT2), CT transformation ratio 1~6000 can be set

Measurement accuracy (25 ℃): Voltage ± 0.5%, current ± 0.5%, frequency ± 0.2Hz, power factor ± 0.02 (CT input ≥ 10% rated value), phase angle ± 2.0 °

Attachment input (auxiliary adjustment): -3V to+3Vcd (1k Ω input impedance), ± 3V corresponds to ± 30% set value offset, used for remote automatic voltage regulator (AVR) or power system stabilizer (PSS) signal input

2.4 Protection and restriction functions

Generator overvoltage protection: 100~120% rated voltage adjustable (1% step), delay 0-10s (1s step), configurable alarm output and/or hardware trip

Magnetic field overvoltage protection: adjustable from 0 to 250Vdc (1V step), fixed delay of 10s, configurable alarm output and/or hardware tripping

Loss of Sense Protection (LOS): It operates when the voltage is below 50% of the rated value or when the three-phase imbalance exceeds 20%. The delay time is adjustable from 0 to 25 seconds (default 10 seconds), and can be configured to turn off or switch to FCR mode

Over excitation limit (OEL): optional summation point or takeover type, current threshold 0-15Adc (0.01A step), delay 0-10s

Underexcitation limit (UEL): reactive power threshold 0~100% rated reactive power (1% step), delay 0~10s

Under frequency (V/Hz) limitation: The inflection point frequency is adjustable from 40 to 65Hz, with a slope of 0 to 3PU (0.01 step), and disabled below 12Hz