Basler DECS-100 Digital Excitation System Debugging Guide

4.4 Loss of Sense Protection Logic and Precautions

When loss of sensitivity is detected, DECS-100 can be configured with two response modes:

Shutdown mode: After a set delay, the DECS-100 will shut off the excitation output and the alarm contact will close.

Switch to FCR mode: After a set delay, the DECS-100 will automatically switch to FCR (manual) mode for operation. Before enabling FCR conversion, it is necessary to pre evaluate and set appropriate FCR settings - inappropriate excitation current levels may cause serious damage to the generator.

Loss of sensation detection is triggered under the following three conditions:

Induced voltage below 50% of rated value (single-phase or three-phase induction)

Complete loss of any phase voltage (three-phase induction)

The difference between any line voltage and the three-phase average value exceeds 20% of the rated value (three-phase induction)

The desensitization function is automatically disabled when the frequency is below 12Hz or when a generator short circuit is detected (B-phase CT current exceeds 3 times the rated value), and is not activated during soft start.

Installation and wiring points

5.1 Mechanical Installation

DECS-100 is designed for panel installation (Figure 4-1, 4-2), and is screwed into the plastic housing of DECS-100 through the installation holes of the generator junction box with 6 # 12 self tapping screws (recommended torque 4.07-4.52N · m). The size of the front panel opening is 101.6mm × 101.6mm. The ambient temperature at the installation location should not exceed the range of -40~+70 ℃.

5.2 Terminal Wiring

All terminals of DECS-100 are located on the rear panel and use 1/4 inch quick connect terminals (Figure 4-3):

Power input (3, 4, 5): single-phase or three-phase 88~250Vac, 50~400Hz. A single phase can be connected to any two phases. When supplying power from a low impedance power source (such as station power or socket), ICRM-7 modules must be connected in series to prevent damage to DECS-100 caused by closing surge current.

Generator voltage induction (E1, E2, E3): Three phase connection E1/E2/E3 (ABC phase sequence), single-phase connection E1 (A phase), E2 and E3 are short circuited and then connected to phase C.

Bus voltage induction (B1, B3): Only voltage matching optional models are available. B1 is connected to phase A, B3 is connected to phase C (non phase sensitive).

B-phase current induction (CT1, CT2): CT1 is connected to CT secondary S1, CT2 is connected to S2. 1A or 5A CT is optional (see style number).

Excitation output (F+, F -): connected to the excitation field of the generator. Output continuous 63Vdc/7Adc, strong excitation 135Vdc/15Vdc (10 seconds).

Alarm output (AL1, AL2): normally open contacts, 7Aac/ADC continuous, closed in case of fault.

Contact inputs: terminals 6U/7 (up), 6D/7 (down), 52J/52K (VAR/PF enabled), 52L/52M (parallel enabled), VM/VMC (voltage matching enabled) - all contacts are dry contacts powered by the internal 13Vdc of DECS-100.

5.3 CE/EMC compliant installation requirements

For CE and EMC compliant installation, DECS-100 must be installed inside a grounded metal enclosure (junction box). The wires connected to the following terminals must use shielded wires, with the shielding layer grounded outside the junction box:

Inductive voltage terminals E1/E2/E3

Alarm output AL1/AL2

External adjustment terminal 6D/7/6U

VAR/PF Enable 52J/52K

Parallel compensation of 52L/52M

Excitation output F+/F-

Power input 3/4/5

Voltage matching VM/VMC

In addition, it is necessary to install ferrite clamps (specifications shown in Table 4-5/4-6) at the wire outlet (25-76mm away from the connector), wound twice, to suppress radiation in the 31-300MHz frequency band.

5.4 Special precautions for power supply in programming state

The PWM power stage input terminal of DECS-100 has a large capacitance, and when powered on from a rigid power source (>120Vac), it will generate a high closing impulse current, which may damage the device. The power supply voltage of DECS-100 in programming state should be limited within the range of 30-120Vac (50/60Hz), and the connection between the F+and F - terminals and the generator magnetic field should be disconnected.

If the power supply voltage exceeds 120Vac during programming, a current limiting resistor -20 Ω/20W (briefly overloaded during impact, with minimal power consumption afterwards) or 10 Ω/50W - must be connected in series between the power supply and DECS-100.

In addition, 24Vdc can also be used for DECS-100 power supply for programming purposes only. Normal operation (PMG or self excitation) is not subject to the above restrictions, but applications powered by station electricity must use ICRM-7 modules to protect DECS-100.

BESTCOMS Software Operation Guide

6.1 Software installation and communication establishment

BESTCOMS-DECS100 software runs on Windows XP/Vista/7/8/10 environment and communicates with DECS-100 through the rear DB-9 RS-232 serial port (default 9600 8N1). The factory default password is "decs". After establishing communication, the software updates the measurement values approximately once per second.