Basler Electric DECS-200 Digital Excitation Control System

Basler Electric DECS-200 Digital Excitation Control System

This instruction manual provides information about the operation and installation of the DECS-200 Digital

Excitation Control System. To accomplish this, the following information is provided:

• General Information and Specifications

• Controls and Indicators

• Functional Description

• Installation

• Maintenance

INTRODUCTION

The Basler Digital Excitation Control System (DECS-200) is a microprocessor-based control device

intended for generator power management. Programmability of system parameters and regulation

settings enables the DECS-200 to be used in a wide range of applications and provides greater flexibility

in excitation system optimization. The DECS-200 can accommodate generator exciter field requirements

up to 15 Adc continuously in 32. 63. or 125 Vdc applications with one model.

FEATURES

DECS-200 units have the following features and capabilities.

Functions

• Four control modes

o Automatic voltage regulation (AVR)

o Manual or field current regulation (FCR)

o Power factor (PF)

o Reactive power (var)

• Soft start buildup with an adjustable ramp in AVR and FCR control modes

• One adjustment range or pre-position setpoint for each control mode

• Overexcitation limiting (OEL) and underexcitation limiting (UEL) in AVR, var and PF control modes

• Twenty stability selections

• Underfrequency compensation or volts per hertz ratio limiter

• Autotracking between operating modes and between DECS-200 units (optional)

• Automatic transfer to a backup DECS-200 unit (optional)

• Eight generator protection features

o Field overvoltage

o Field overcurrent

o Generator overvoltage

o Generator undervoltage

o Watchdog timer

o Loss of sensing

o Exciter diode monitor (EDM)

o Loss of field

• Generator paralleling with reactive droop compensation and reactive differential compensation

• Data logging and event recording

Inputs and Outputs

• Single-phase rms bus voltage sensing

• Single-phase or three-phase rms generator voltage sensing

• Single-phase generator current sensing (1 or 5 amperes, nominal)

• Analog inputs (±10 Vdc and 4 to 20 mAdc) provide proportional, remote control of the setpoint

• Eleven PLC-compatible contact sensing inputs for system interface

• Separate ac and dc power inputs accommodate redundant operating power sources

• Pulse-width modulated output power stage rated at a maximum of 15 amperes, continuous

• Five output relays for system control or annunciation

o Three programmable output relays

o Two fixed-function output relays

HMI Interface

• Front panel HMI includes pushbutton controls, LED indicators and a backlit, liquid crystal display

(LCD)

• BESTCOMS™ Windows® based software provides easy, fast and accurate setup and control

Three communication ports

o Front RS-232 port for communication with a PC using BESTCOMS software

o Right-side panel RS-232 port for dedicated communication with a redundant DECS-200

o RS-485 communication port for communication with a remote terminal

• Modbus protocol for the RS-485 port allows communication at distances of up to 1.200 meters

(3.937 feet)

Introduction

In the typical application shown in Figure 1-1. the DECS-200 controls the exciter field of a synchronous

generator. Front panel controls, indicators, and serial communication ports using PC software make the

system easy to operate locally or from remote locations. DECS-200 operation, settings, and safety setup

procedures in this manual should be studied before implementing your application. For detailed

application assistance, contact Basler Electric or your local sales representative.

Operating Power

Operating power for the pulse-width modulated (PWM) excitation output is typically obtained from the

generator output through a power transformer. Alternately, operating power can be supplied from a

permanent magnet generator (PMG).

During DECS-200 power-up, an optional ICRM (Inrush Current Reduction Module) prevents damage to

the DECS-200 by limiting inrush current to a safe level. For more information, refer to Section 4.

Installation.

Control Power

If power supply option C (120/125 Vac/Vdc) is selected, a redundant power source can be used with the

DECS-200. (See Figure 1-1.) In this configuration, if one of the two sources fails, the other source will

continue to supply DECS-200 operating power. If power supply option L (24/48 Vdc) is selected, no

redundant power source is available.

Sensing

The DECS-200 senses generator voltage and current through voltage and current transformers. Field

voltage and field current values are sensed internally.

Excitation Limiters

Integrated overexcitation and underexcitation limiters (OEL and UEL) are available for both on-line and

off-line protection.

External Tracking and Transfer Between DECS-200 Units (Optional)

For critical applications, a second DECS-200 can provide backup excitation control. The DECS-200

allows for excitation system redundancy by providing external tracking and transfer provisions between

DECS-200 units. The secondary DECS-200 operating modes can be programmed to track the primary

DECS-200 operating mode. Proper, redundant excitation system design allows for removal of the failed

system. Periodic testing of the backup system must be performed to ensure that it is operational and can

be put into service without warning.

Internal Tracking Between DECS-200 Operating Modes

In applications using a single DECS-200. the DECS-200 can be programmed so that the inactive

operating modes track the active operating mode. Operating modes include AVR, FCR, PF, and var. If

the excitation system is normally operating on-line in Internal mode and a loss of sensing occurs, the

DECS-200 could be transferred to manual (FCR) mode where the loss of sensing has no impact on the

exciter's ability to maintain proper excitation levels. While performing routine testing of the DECS-200 in

backup mode, the internal tracking feature allows a transfer to an inactive mode that will result in no

disturbance to the system.

Communication With a PC

Communication between the DECS-200 (front panel RS-232 port) and a PC is possible through

BESTCOMS software. BESTCOMS enables fast and easy programming of setpoints and ranges and

allows for step changes to facilitate proper stability settings. BESTCOMS also provides easy start and

stop control and operator adjustment of the excitation system with real-time metering. The software

catalog number is BESTCOMS-DECS200. BESTCOMS is provided with the DECS-200 as part of the

software/manual package.

Sample Style Number

The style number identification chart (Figure 1-2) defines the electrical characteristics and operational

features included in the DECS-200. For example, if the style number were DECS-200-1L, the device

would have the following characteristics and features.

DECS-200  -- Digital Excitation Control System

1 --- Internal autotracking/transfer

L --- 24/48 Vdc control power supply

SPECIFICATIONS

DECS-200 electrical and physical characteristics are listed in the following paragraphs.

Control Power

Input Voltage

DC Input: 16 to 60 Vdc (style XL) or 90 to 150 Vdc (style XC)

AC Input: 85 to 132 Vac, 50/60 Hz (style XC only)

Note: Isolation transformer for ac input is required when dual control

power sources are used.

Burden

DC Input: 30 W

AC Input: 50 VA

Terminals

DC Input: B7 (+), B8 (–)

AC Input: B9 (L), B10 (N) (style XC only)

Operating Power

To achieve the proper DECS-200 output voltage, the appropriate operating power input voltage must be

provided.

32 Vdc PWM Output

Nominal: 60 Vac

Operating Range: 56 to 70 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 780 VA

63 Vdc PWM Output

Nominal: 120 Vac

Operating Range: 100 to 139 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 1.570 VA

125 Vdc PWM Output

Nominal: 240 Vac

Operating Range: 190 to 277 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 3.070 VA

Voltage Buildup

From a minimum of 3 Vac

Terminals

C2 (A-phase), C3 (B-phase), C4 (C-phase)

Sample Style Number

The style number identification chart (Figure 1-2) defines the electrical characteristics and operational

features included in the DECS-200. For example, if the style number were DECS-200-1L, the device

would have the following characteristics and features.

DECS-200  -- Digital Excitation Control System

1 --- Internal autotracking/transfer

L --- 24/48 Vdc control power supply

SPECIFICATIONS

DECS-200 electrical and physical characteristics are listed in the following paragraphs.

Control Power

Input Voltage

DC Input: 16 to 60 Vdc (style XL) or 90 to 150 Vdc (style XC)

AC Input: 85 to 132 Vac, 50/60 Hz (style XC only)

Note: Isolation transformer for ac input is required when dual control

power sources are used.

Burden

DC Input: 30 W

AC Input: 50 VA

Terminals

DC Input: B7 (+), B8 (–)

AC Input: B9 (L), B10 (N) (style XC only)

Operating Power

To achieve the proper DECS-200 output voltage, the appropriate operating power input voltage must be

provided.

32 Vdc PWM Output

Nominal: 60 Vac

Operating Range: 56 to 70 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 780 VA

63 Vdc PWM Output

Nominal: 120 Vac

Operating Range: 100 to 139 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 1.570 VA

125 Vdc PWM Output

Nominal: 240 Vac

Operating Range: 190 to 277 Vac, ±10%

Frequency Range: 50 to 500 Hz

Configuration: 1-phase or 3-phase

Burden: 3.070 VA

Voltage Buildup

From a minimum of 3 Vac

Terminals

C2 (A-phase), C3 (B-phase), C4 (C-phase)

Burden: <1 VA per phase

Terminals: A1. A2. A3

50 Hertz Sensing

Range 1: 100 Vac (85 to 127 Vac)

Range 2: 200 Vac (170 to 254 Vac)

Range 3: 400 Vac (340 to 508 Vac)

Range 4: 500 Vac (425 to 625 Vac)

60 Hertz Sensing

Range 1: 120 Vac (94 to 153 Vac)

Range 2: 240 Vac (187 to 305 Vac)

Range 3: 400 Vac (374 to 600 Vac)

Range 4: 600 Vac (510 to 660 Vac)

Generator Current Sensing

Type: Two ranges, two channels

Frequency: 50/60 Hz

Ranges: 1 A or 5 A nominal, continuous

Burden: <1 VA per phase

Terminals

1 A Sensing: B1. B3 (phase B, metering, var/PF, UEL)

B4. B6 (phase B, crosscurrent compensation)

5 A Sensing: B2. B3 (phase B, metering, var/PF, UEL)

B5. B6 (phase B, crosscurrent compensation)

Bus Voltage Sensing

Type: 1-phase, 4 ranges,

Burden: <1 VA

Sensing Ranges: Identical to generator voltage sensing

Terminals: A4. A5

Accessory Inputs

Current Input

Range: 4 to 20 mAdc

Terminals: A6 (+), A7 (–)

Voltage Input

Range: –10 to +10 Vdc

Terminals: A9 (+), A10 (–)

Communication Ports

Interface

RS-232: Full duplex

RS-485: Half duplex

Connections

Com 0: Front panel DB-9 connector

Com 1: Right-side panel DB-9 connector

Com 2: Left-side panel screw terminals (A43. A44. A45)

Parameters

Baud: 1200 to 19200

Data Bits: 8

Parity: None

Stop Bits: 1 (Com 0. Com 1) or 2 (Com 2)

Contact Inputs

Type: Dry contact; accept PLC open-collector outputs

Interrogation Voltage: 12 Vdc

Terminal Assignments

Start: A21. A22

Stop: A23. A24

Auto (AVR): A25. A26

Manual (FCR): A27. A28

Raise: A29. A30

Lower: A31. A32

Pre-Position: A33. A34

Unit/Parallel (52L/M): A35. A36

Var/PF (52J/K): A37. A38

Secondary Enable: A39. A40

Alarm Reset: A41. A42

Contact Outputs

Make and Break Ratings (Resistive)

24 Vdc: 7.0 A

48 Vdc: 0.7 A

125 Vdc: 0.2 A

120/240 Vac: 7.0 A

Carry Ratings (Resistive)

24/48/125 Vdc: 7.0 A

120/240 Vac: 7.0 A

Terminal Assignments

Start/Stop (ON, OF): A11. A12

Watchdog (WTCHD): A13. A14

Relay 1 (RLY1): A15. A16

Relay 2 (RLY2): A17. A18

Relay 3 (RLY3): A19. A20

Field Output

Continuous Output Rating

60 Vac Input: 32 Vdc, 15 Adc

120 Vac Input: 63 Vdc, 15 Adc

240 Vac Input: 125 Vdc, 15 Adc

10 Second Forcing Output Rating

60 Vac Input: 50 Vdc, 30 Adc

120 Vac Input: 100 Vdc, 30 Adc

240 Vac Input: 200 Vdc, 30 Adc

Minimum Field Resistance

32 Vdc Application: 2.13 Ω

63 Vdc Application: 4.2 Ω

125 Vdc Application: 8.3 Ω

Regulation

AVR Operating Mode

Accuracy: ±0.25% over load range at rated PF and constant generator frequency

Steady State Stability: ±0.1% at constant load and generator frequency

Temperature Drift: ±0.5% for a 0 to 50°C change

V/Hz Characteristic: Slope from 0 to 3 PU is adjust-able in 0.1 PU increments. Voltage

regulation error is within ±2.0% of the nominal voltage.

Response Time: <1 cycle