Home Product SalesPower SolutionsLS-AES Excitation System
Photo of LS-AES Excitation Controller

LS-AES Excitation System

LS-AES is the only exciter system that's backed by L&S Electric's reputation for quality and a team with over 175 years combined experience in excitation control and systems!

LS-AES Excitation System

The LS-AES, the newest Exciter System in the industry. The only exciter system backed by the L&S Electric, Inc. quality reputation, and a team of experts with over 175 years of combined engineering experience in excitation systems and control.

  • Provides a more flexible and cost-effective alternative to the proprietary excitation system
    controllers currently available
  • Designed with proven technologies and control algorithms developed by experienced professionals
    in the excitation field
  • Built with state of the art powerful open architecture industrial controllers, OIT’s and IED’s
  • Fully tested and simulated at L&S Electric’s state of the art in-house laboratory
  • Commissioned and serviced directly by L&S Electric’s field service and engineering professionals
  • After sales support, 24 hours a day, 7 days a week, and 365 days a year 
  • 2-year standard warranty

Excitation Controllers and Standards

LS-AES Excitation Controller Models: LS-ECO and LS-EXC

  • Generator Voltage Sensing
    • 3-phase/4 phases
  • Bus. Voltage Sensing
    • 1-phase for voltage matching
  • General Current Sensing
    • Configuration
      • 3-phase with no cross-current compensation
      • 1-phase with cross-current compensation
    • Range
      • 1 or 5 AC nominal
    • Frequency
      • 50 or 60 Hz nominal
  • Controller CPU
    • LS-ECO: 1 GHz
    • LS-EXC: 1.4 GHz, 64-bit
  • I/O Interface
    • Discrete Inputs
      • LS-ECO: 16
      • LS-EXC: 32
    • Discrete Outputs
      • LS-ECO: 16
      • LS-EXC: 16
    • Analog Input
      • +/- 10 VDC
        • LS-ECO: 4
        • LS-EXC: 4
      • 4-20 mA
        • LS-ECO: 0
        • LS-EXC: 4
    • Analog Outputs
      • +/- 10 VDC
        • LS-ECO: 1
        • LS-EXC: 1
      • 4-20 mA
        • LS-ECO: 8
        • LS-EXC: 8

All LS-AES are designed to meet the highest standards

  • IEEE-421.1 Standard definition for excitation system for synchronous machines
  • IEEE-421.2 Guide for identification, testing, and evaluation of the dynamic performance of excitation control systems
  • IEEE-421.3 Standard high-potential test requirements for excitation systems for synchronous machines
  • IEEE-421.4 Guide for the preparation of excitation system specifications
  • IEEE-421.5 Recommended practice for excitation system models for power system stability studies
  • IEEE-C37.2 Standard electrical power system device function numbers and contact designations
  • IEEE-C37.18 Field discharge circuit breakers for rotating electric machinery
  • IEEE-C37.20.1 Metal-enclosed low-voltage power circuit breaker switchgear
  • IEEE-C37.90.1 Standard for surge withstand capability (SWC) tests for relays and relay systems associated with electric power apparatus
  • IEEE-C57.18.10 Standard practices and requirements for semiconductor power rectifier transformers 500kW and above
  • IEEE-C57.13 Standard requirements for instrument transformers
  • IEEE-C37.102 Guide for AC generator protection
  • ANSI-C57.12.01 General requirements for dry-type distribution and power transformers
  • IEC-60146-1-1 Semiconductor converters general requirements and line commutated converters Part 1-1
  • NERC PRG019 Coordination of generating unit or plant capabilities, voltage regulating controls and protection
  • NERC MOD-026 Verification and models and data for generator excitation control systems or plant Volt/VAR control functions

LS-AES-VR-* Automatic Voltage Regulator

LS-AES-VR-ECO Automatic Voltage Regulator

  • Simplex configuration
  • L&S controller: LS-ECO
  • 3.4" monochrome touch panel operator interface
  • L&S Thyristor bridge
    • 50A nominal, 480VAC, full wave, 6 SCR design for negative forcing
    • 40C ambient nominal design
    • Natural convection cooled
    • Bridge over temperature, alarm and protection
    • (1) fuse on each AC line
  • Digital firing board
  • MOVs for overvoltage protection
  • Standard protection and limiter functions
  • AC field breaker, standard
  • System control power supply: (1) universal input, 110-300 -20/+25% VDC / 100-240 +/- 15% VAC to 24VDC power converter, 20A
  • Options
    • PSS2B only
    • 15" graphical touch screen HMI
    • AC field flashing assembly preferred
    • DC field flashing assembly available
    • SEL 700G relay for exciter protection
    • SEL 2664 relay for field ground detection
    • Exciter power transformer (EPT)
    • Redundant power supply
    • DC Field Breaker

LS_AES-VR-EXC Automatic Voltage Regulator

  • Simplex or redundant configuration
  • L&S Controller: LS-EXC
  • 3.4" monochrome touch panel operator interface
  • L&S Thyristor bridge
    • 50A nominal, 480VAC, full wave, 6 SCR design, for negative forcing
    • 40C ambient nominal design
    • Natural convection cooled
    • Bridge over temperature, alarm and protection
    • (1) fuse on each AC line
  • Digital firing board
  • MOVs for overvoltage protection
  • Standard protection and limiter functions
  • AC field breaker, standard
  • System control power supply: (1) universal input 110-300 -20/+25% VDC / 100-240 +/- 15 VAC to 24 VDC power converter, 20A
  • Options
    • PSS2B or PSS48
    • 15" graphical touch screen
    • AC field flashing assembly preferred
    • DC field flashing assembly available
    • SEL 700G relay for exciter protection
    • SEL 2664 relay for ground detection
    • Exciter power transformer (EPT)
    • Redundant power supply
    • DC field breaker
    • Redundancy on controller and/or bridge: 1+1

LS-AES-FS-*-* Full Static Excitation System

LS-AES-FS-ECO

  • Simplex configuration
  • High initial response (HIR) as per IEEE 421.1
  • Designed to meet or exceed ANSI-C50-13 overload requirements
  • L&S Controller: LS-ECO
  • 3.4" monochrome touch panel operator interface
  • L&S Thyristor bridge
    • 200A nominal, 480VAC, full wave, 6 SCR design for negative forcing
    • 40C ambient nominal design
    • Forced air cooled with redundant fans, standard
    • Bridge over temperature, alarm and protection
    • (1) fuse on each AC line with blown detection
  • Digital firing board
  • AC field breaker, standard
  • AC field flashing, standard
  • Standard protection and limiter functions
  • MOVs for overvoltage protection, standard
  • System control power supply: (1) universal input 110-300 -20/+25% VDC / 100-240 +/- 15% VAC to 24 VDC power converter, 20A
  • Options
    • PSS2B only
    • DC field flashing
    • SEL 700G relay for exciter and EPT protection
    • SEL 2664 relay for field ground detection
    • Exciter power transformer (EPT)
    • Redundant power supply
    • Crowbar with linear resistor for over-voltage protection
    • Custom bridge sizes may be available - refer questions to engineering
    • 15" graphical touch screen HMI

LS-AES-FS-EXC-DT

  • Simplex or redundant configuration
  • High initial response (HIR) as per IEEE 421.2
  • Designed to meet or exceed ANSI-C50-13 overload requirements
  • L&S controller: LS-EXC
  • 3.4" monochrome touch panel operator interface
  • 15" graphical touch screen HMI
  • L&S Thyristor bridge
    • Full wave, 6 SCR design, negative forcing
    • 40C ambient nominal design
    • Forced air-cooled with redundant fans, standard
    • Bridge over temperature, alarm and protection
    • (1) fuse on each SCR AC branch for bridges above 400A. (6) total
    • Available sizes
      • 200A, 480 VAC
      • 400A, 480 VAC
      • 800A, 600 VAC
      • 1500A, 800 VAC
  • Digital firing board
  • Crowbar with linear resistor for overvoltage protection, standard
  • AC field breaker, standard
  • AC field flashing, standard
  • Standard protection and limiter functions
  • System control power supply: (2) universal input 110-300 -20/ +25% VDC / 100-240 +/- 15% VAC to 24 VDC power converter, 20A
  • Options
    • PSS2B or PSS4B
    • Bridge redundancy on controller and/or bridge: 1+1
    • DC field flashing
    • DC field breaker
    • SEL 700G relay for exciter and EPT protection
    • SEL 2664 relay for field ground detection
    • Exciter power transformer (EPT)
    • Redundant power supply
    • Crowbar with non-linear resistor

Excitation Controller Features

  LS-ECO LS-EXC
IEC-61131-3 Programming Yes Yes
True RMS Sensing Yes Yes
Digital Regulation and Control Yes Yes
<0.20% voltage sensing of rated full-scale DC output Yes Yes
+/- <0.05 voltage regulation accuracy Yes Yes
Generator over-voltage protection (59) Yes Yes
Field overcurrent protection (51E) Yes Yes
Field over-voltage protection (59E) Yes Yes
Loss of voltage sensing protection (60LOP) Yes Yes
Loss of field protection (40) Yes Yes
Volts/Hertz protection (24) Yes Yes
Field over temperature protection No Yes
Exciter power transformer over temperature protection (26EPT) No Yes, discrete input
Thyristor bridge temperature monitoring Yes Yes
Field flashing failure protection (48FF) Yes Yes
Watchdog Yes Yes
Volt/Hertz limiter (VHL) Yes Yes
Terminal voltage limiter (TVL) Yes Yes
Over-excitation limiter (OEL) Yes Yes
Under excitation limiter (UEL) Yes Yes
Stator current limiter (SCL) Yes Yes
Instantaneous field current limiter (INS) Yes Yes
Reactive current compensator (Droop/Drop) Yes Yes
Cross current compensation (CCC) Yes Yes
Step response for model validation Yes Yes
PID control Yes Yes
Local and remote control Yes Yes
Auto and manual channels Yes Yes
Automatic - manual follower Yes Yes
Bumpless transfer between channels Yes Yes
Generator soft start Yes Yes
VAR or power factor control mode Yes Yes
Field current or field voltage regulation (manual) control mode Yes Yes
Voltage control mode (auto) Yes Yes
Voltage matching Yes Yes
Power system stabilizer Optional (2B) Optional (2B & 4B)
Rotating exciter diode monitoring Yes Yes
Negative field forcing Yes Yes
Disturbance/transient analysis data logging @ 4 msec sample rate No Yes, Comtrade
Real-time trending @ 4 msec sample rate for turning (scope) Yes, using LS-ACT Yes, using LS-ACT
True wave oscillography @ 2 kHz sample rate No Yes, Comtrade
Sequence of events No Yes
Event logging (historical/active alarms) Yes, with 15" HMI Yes, with 15" HMI
Historical trending Yes, with 15" HMI Yes, with 15" HMI
User-friendly LS-ACT (MS Windows-based configuration and maintenance tool for system tuning, configuration, and setup Yes Yes
Additional configurable DI and DO Custom if required Custom if required
Additional configurable AI and AO Custom if required Custom if required
Serial port - Modbus RTU for local OIT Yes Yes
Modbus TCP/IP for remote communications Yes Yes
Ethernet - DNP3 Optional Optional
IEC-60870...101 or 104 No Optional
IEC-61850 No Optional
IRG-B time synchonization Yes Yes
NTP time synchonization Yes Yes
PTP time synchonization No Optional
Redundant electronics (1+1) No Optional
Redundant bridges (1+1) No Optional
Field ground detection Optional Optional
User configurable logic, using controller programming software Yes Yes