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Overview

The DECS-250E Digital Excitation Control System provides accurate and

reliable regulation, control, and protection for synchronous motors or

generators. Three DECS-250E models can supply a maximum of 50 Adc, 100

Adc, or 200 Adc of excitation current in a static or rotary exciter application. All

DECS-250E components are housed in a compact enclosure which makes for

a simple and cost-effective installation for a wide variety of applications.

Benefits

• Reduce your setup time with Basler’s intuitive BESTCOMSPlus®

software that simplifies complex setup with simple drag-and-drop

programmable logic, visual real-time strip chart capabilities, and

cutting edge auto PID selection capabilities.

• The auto tuning function automatically establishes optimum PID

and gain settings, taking the guesswork out of system setup,

reducing commissioning time and cost while maximizing overall

system performance.

• The Offline Simulator in BESTlogic™Plus helps test and

troubleshoot logic without expensive hardware.

• A 50. 100. 200 ampere positive forcing rectifier bridge can be

selected to provide optimum response to the generator main field

or exciter field.

Each DECS-2100 system is equipped with a default HMI on the logic cubicle door.

The default (local HMI uses one of two available Ethernet ports on the ECM-2

module. Each DECS-2100 system also contains one additional Ethernet port that

may be used for a remote HMI, as a connection to another plant control system,

or to an Ethernet switch so that multiple devices can gather data.

Basler Electric recommends that the DECS-2100 be placed on a dedicated network.

Placing it on an “open network” may cause unwanted communication errors.

Software

BESTCOMSPro software provides the ability to set Ethernet addressing on the

two ECM-2 Ethernet ports. Each port gathers data from the same data maps so

the information is identical.

Once the user is connected to the controller via BESTCOMSPro, the Ethernet

ports can be configured in the Settings Explorer (General Settings, Controller

Settings, Ethernet Settings). Ethernet 1 and Ethernet 2 are set independently.

Hardware

Each ECM-2 module is equipped with two Ethernet ports which use an RJ-45

connector. Port 2 is typically used for communication with the local HMI on the

door of the DECS-2100 enclosure. Each ECM-2 (on per channel) would be linked

from Ethernet port 2 to an Ethernet switch also linked to the local HMI.

The ECM-2 supports 10Base-T and 100Base-T wiring standards.

The user could connect their plant SCADA system or other Ethernet master to the

Ethernet switch providing the signal to the HMI. However, the same IP addresses

would need to be used for the ECM2 modules. Alternately, the user could connect

the plant SCADA to Ethernet port 1—either directly or through a separate Ethernet

switch. Due to communication issues, Basler Electric prefers the use of Ethernet

port 1 for communication with external plant devices and the use of Ethernet port

2 for the local HMI only.

Product Features & Benefits

• A wide variety of redundancy options increases system reliability.

• An available suite of limiters coordinates with protective functions to help

maintain safe operating parameters and avoid system downtime.

• Various protection functions are integrated into the controller to avoid system

damage.

• Dual gain settings can maximize excitation system performance based on load

conditions.

• Improve system reliability and stability by coordinating dual settings groups for

limiters and protection to match generation system conditions.

• A soft start feature maintains generator voltage control during system startup

to prevent undesired overshoots.

• Time synchronizing provisions facilitate event analysis with a common chronological

reference to aid in coordination efforts when comparing oscillography files from other

devices.

• Real-time monitoring and built-in test provisions simplify system testing and reduce

commissioning time.

• Entering settings with confidence is easy with BESTCOMS™Pro. Software provides

intuitive settings with graphs, built-in error checking, and summary screens.

• Power Drawers allow for simple online and offline maintenance of complete rectifier

bridges that can reduce or eliminate exciter down time.

• Sequence of Events and Oscillography Recording provisions collect valuable system

data triggered by disturbances for event analysis.

• Avoid costly generator damage and improve overall system stability with Basler

Electric’s integrated Power System Stabilizer (optional) that utilizes the “integral of

accelerating power” to safely dampen local mode, inter-area and inter-unit power

oscillations.

• Basler’s in-house engineering, fabrication, manufacturing, and test capabilities

provide maximum control of processes and product design, resulting in the highest

quality and maximum reliability while offering shorter lead times.

• Optional supervisory channel increases system security by avoiding inadvertent

tripping with two-out-of-three controller comparison technique.

Ethernet communication reduces the amount of hardwiring needed for alarm and

status signals while increasing

the amount of information available. This information may be used to interface

with external distributed control

systems such as SCADA, etc.

The DECS-2100 is an extremely powerful and flexible excitation system that

precisely controls, protects, and monitors synchronous generators and motors.

Its multifunctional design allows it to operate in a wide range of applications

that require excitation currents up to 10.000 Adc.

The BESTCOMS™Pro software program complements the DECS-2100 by

embedding many time-saving tools such as programmable logic, integrated

simulator, system monitoring, commissioning, event viewing, system settings

and configuration, and an extensive Help function into one program.

— Product Features & Benefits

• A wide variety of redundancy options increases system reliability.

• An available suite of limiters coordinates with protective functions to help

maintain safe operating parameters and avoid system downtime.

• Various protection functions are integrated into the controller to avoid system

damage.

• Dual gain settings can maximize excitation system performance based on load

conditions.

• Improve system reliability and stability by coordinating dual settings groups for

limiters and protection to match generation system conditions.

• A soft start feature maintains generator voltage control during system startup

to prevent undesired overshoots.

• Time synchronizing provisions facilitate event analysis with a common chronological

reference to aid in coordination efforts when comparing oscillography files from other

devices.

Overview

A microprocessor-based relay that provides versatility and control in

automatic circuit breaker reclosing.

Features

• Ability to resume reclosing sequence if control power is interrupted.

• Individually adjustable time-delayed reclosing attempts.

• Separate high speed pilot reclose input and output are available for

transmission reclosing applications.

• Self-monitoring circuitry with alarm output.

• Optional controls limit the duration of reclose command output and the

overall reclosing cycle.

• Optional contact inputs can be used to inhibit the reset timer, inhibit

all reclose timing, obtain an alarm prior to lockout, or permit a special

reclosing sequence.

Benefits

• Program up to four reclosure attempts with contact-selectable

reclosing sequences.

• Gain flexibility with individually adjustable time-delayed reclosing

attempts.

• Optional outputs provide control for tripping schemes and blocking

load tap-changer operation during reclosing sequences.

• Reduced battery load with low burden power supply.

• Easily perform in-case system and device tests using test paddles.

BE1-64F relays are compatible with continuous field voltages up to 600 Vdc

and forcing voltages up to 750 Vdc for one minute. During reverse excitation

(negative forcing), BE1-64F relays will withstand up to 1.200 Vdc for one

minute.

Features

• BE1-64F models with connections to either the positive or negative

side of the exciter or main field of the machine are available.

• Detects field grounds on motors and generators.

• Two-level detection for pre-alarm and trip.

• Compact, draw-out case.

• Test function.

• Nonvolatile storage of trip target state.

Benefits

• Pre-alarm allows action to prevent a trip.

• Accurate, repeatable, and reliable operation.

• Simplified installation with no settings required.

• Retrofit into cutout made for ITE/BBC/ABB/GE field ground relays.

Overview

The BE1-64F relays are designed to detect unintentional grounding in field

windings of a synchronous generator or motor. Two fixed levels of ground

detection are provided: a prealarm level and a trip level. Each level has an

independent LED indicator and output contact.

The BE1-64F Ground Fault Relay detects and annunciates ground faults in

the normally ungrounded field circuit of a synchronous machine.

A short-circuit in a synchronous machine’s field can often be prevented

by detecting and removing a ground fault before a second ground fault

results in serious damage.

BE1-64F relays are compatible with continuous field voltages up to 600 Vdc

and forcing voltages up to 750 Vdc for one minute. During reverse excitation

(negative forcing), BE1-64F relays will withstand up to 1.200 Vdc for one

minute.

Two sets of relay outputs and front panel indicators are provided for fault

annunciation and tripping duty. One set of output contacts, one front panel

indicator, and a latching target indicator annunciate the detection of a ground

fault in the field winding. A second set of output contacts and a front panel

indicator annunciate the detection of lower than normal resistance across the

field winding and ground.

Replacement of an ABB 64F with the BE1-64F is simplified because the panel

cutout and drilling pattern for the BE1-64F matches that of the ABB 64F.

Protection

Protection of capacitor banks has always been difficult. It is especially difficult to

sense failures inside the capacitor banks because of the configuration.

Experience indicates that most capacitor bank faults involve one or more insulator

failures with arcing across groups and/or phase-to-phase inside the bank. In most

cases, these types of faults are not seen by the bus differential or other protection

unless the arcing spills over to the area between the fuses and the circuit switcher.

A fault across an insulator usually means that one or more groups of parallel units

are shorted. This will cause a neutral shift and unbalanced phase currents.

Unbalanced phase current magnitudes are determined by the number of series

connected groups. For full phase-to-neutral flashover, the maximum phase current

is three times normal capacitor bank load in the faulted phase.

One main protection concern is overvoltage cascading. A capacitor bank is unique

in that cascading of units may take place after a predetermined number of unit

fuses have operated. Normally after a fuse has blown in any other type of equipment,

the faulted apparatus is disconnected and usually does not affect any remaining

equipment that is in service. That is not so with a capacitor bank. Each fuse that

blows to isolate the faulted unit sets up an increased voltage stress on the remaining

 units (Figure 1-1). Sometime later, the next weakest unit in that group fails.

As each successive fuse blows, the voltage increases another step and rapidly causes

the next unit to fail. Cascading takes place and results in serious damage to the

capacitor bank and possible hazards to personnel. While the capacitor bank is failing,

the station in minimally affected. The voltage is nearly normal, the current flow is almost

unaffected, and station relay protection is not taking any action until the failure has

developed into a phase-to-phase or phase-to-ground fault.

A solution was to develop a protective scheme for the capacitor bank with the main

emphasis on preventing overvoltage cascading. To do this, a ground fault relay or neutral

shift device had to be developed that was sensitive enough to detect blown fuses for both

alarming and tripping purposes. The best place to obtain the sensing information is

between the neutral of the capacitor bank and ground.

Voltage differentials between the normal capacitor bank status and that of one blown

fuse are very small.

However, BE1-59NC relays are sensitive enough to differentiate between these conditions

and act decisively.

Application

Capacitor banks are widely used by utilities to maintain specified system voltage.

Addition of capacitive loads at appropriate points on the system compensate for

heavy inductive loading that normally tends to reduce voltage.

This adding of leading megavars to compensate for the lagging megavar

component of electric loads is frequently referred to as power factor correction.

Capacitor banks must be switched in response to actual load conditions in order

to obtain maximum power factor correction benefits.

Capacitor Bank Switching

One of the common methods of maximizing capacitor bank benefits is by evaluating

the bus voltage. A bandwidth surrounding the desired bus voltage level is

established. When the bus voltage falls below the bandwidth level, the capacitor

bank is switched into the circuit. When the bus voltage rises above the bandwidth

level, the capacitor bank is switched out.