Basler DECS-100 Digital Excitation System Debugging Guide

6.2 Setting value modification and storage

All set values can be modified by following these steps: select the corresponding tab → click on the set value field → enter the new value → click on the SendToDECS button (or press Enter) → click on the EEPROM button to save to non-volatile memory. Attention: The erase and write life of non-volatile memory is about 10000 times, and it is necessary to plan frequent write operations reasonably.

6.3 Key Setting Parameters

System Configuration: Induced voltage type (single-phase/three-phase), limiter enable (OEL/UEL), OEL type (summation point/connection), generator frequency (50/60Hz), PT/CT ratio

Setting Adjustments: AVR setting value, FCR setting value, VAR/PF setting value, droop percentage (0-10%), fine voltage regulation bandwidth (0-15%)

Control Gain: Stable range (1-20 preset groups or 21 custom), PID parameters (Kp/Ki/Kd/Td/Kg)

Protection: overvoltage/overexcitation/loss of inductance/underexcitation protection threshold and delay, hardware shutdown enable

Startup: Soft start time, under frequency inflection point frequency and slope, voltage matching speed and mode

6.4 Step Response Analysis Tool

The Analysis screen supports step response testing in four modes: AVR, FCR, VAR, and PF (Figure 5-10 to 5-13). Users can set step increments/decrements of 0-10%, observe real-time responses of Vrms, Ifd, reactive power, and power factor, and use six alarm signals for on-site PID parameter optimization verification.

6.5 Firmware Upgrade

The embedded firmware of DECS-100 is stored in programmable flash memory and can be upgraded online through BESTCOMS' DECSLoad function (communication needs to be turned off first). Interruption of power or communication during the upgrade process will result in the inability of DECS-100 to recover. Before upgrading, the current setting value file (. de1) must be saved, and the F+/F - terminals must be disconnected to avoid accidental excitation output.

Common troubleshooting guide

Troubleshooting steps for fault phenomena

Generator voltage cannot be established ① Check all wiring (Figures 4-6 to 4-10); ② Confirm that the generator has reached its rated speed; ③ Check the input power supply during PMG power supply (refer to the specification sheet); ④ Check if the residual voltage during self excitation is ≥ 6Vac (if not, magnetize); ⑤ Check if there is a blown fuse; ⑥ Confirm that the over excitation turn off LED is not on (if it is on, check the load, power off for 1 minute and reset); ⑦ Confirm that the overexcitation limit LED is not on; ⑧ Check if the soft start setting value is too long; ⑨ Replace DECS-100

Low generator voltage ① Check if the voltage setting value is too low; ② Check if the set value of the underfrequency inflection point is higher than the actual frequency; ③ Confirm that the generator has reached its rated speed; ④ Check the input power supply voltage during PMG power supply; ⑤ Check the PT ratio and capacity during self excitation; ⑥ Confirm that the overexcitation limit LED is not on; ⑦ Check the impact of inductive loads in droop mode; ⑧ Check if the attachment input has changed the set value; ⑨ Replace DECS-100

High frequency motor voltage ① Check if the voltage setting value is too high; ② Check if the induction PT ratio is correct; ③ Check the impact of capacitive load sagging; ④ Check the impact of attachment input; ⑤ Replace DECS-100

Unstable voltage regulation (traveling block) ① Confirm that the casing is well grounded (GND terminal); ② Check if the excitation lead is grounded; ③ Check the grounding of PMG leads during PMG power supply; ④ Confirm that the load is not lower than the underfrequency inflection point; ⑤ Confirm that it is not affected by sagging mode; ⑥ Check if the Stability Range is correct; ⑦ Check if the Stability Level is correct; ⑧ Replace DECS-100

Overexcitation shutdown indicator ① Check if the generator is overloaded; ② Confirm that the excitation voltage requirement is compatible with the DECS-100 output; ③ Replace DECS-100; ④ Check for generator malfunction

Loss of sensitivity indicator ① Check the connection of voltage sensing leads; ② Confirm that E2 and E3 are connected to phase C simultaneously during single-phase induction; ③ Check the sensing PT ratio and function; ④ Confirm the balance of three-phase voltage; ⑤ Replace DECS-100

No sagging ① Confirm that the 52L/M contact is disconnected; ② Confirm that the 52J/K contact is closed or the VAR/PF function software is disabled; ③ Confirm that the sag setting value is greater than 0%; ④ Check that there is no open circuit in the CT1/CT2 circuit; ⑤ Confirm that the wiring is correct; ⑥ Confirm that the load contains inductive components; ⑦ Confirm CT ratio matching (1A CT for 5A input without droop); ⑧ Replace DECS-100

No voltage matching ① Confirm that the voltage matching option is selected and the software is enabled; ② Confirm that the wiring is correct; ③ Confirm that the VM/VMC contacts are closed; ④ Confirm that the B1/B3 terminals have the correct bus reference voltage; ⑤ Confirm that the set value of the generator is within 10% of the bus voltage range; ⑥ Replace DECS-100