Power management system (PMS)

The Mega-Guard Power Management System (PMS) is an advanced system for full automation of power plants


PMS Operator PanelThe Mega-Guard Power Management Sytem (PMS) is an advanced system for full automation of power plant, including power management, diesel engine control, generator control, synchronizing, generator protection and optional diesel engine safety system. Each generator set is equipped with its own independent and autonomous PMS system. This ensures the highest degree of reliability and availability. The Mega-Guard PMS is supplied as a complete product and no additional components are needed for automation of a low voltage switchboard up to 690VAC.

The graphic display clearly indicates breaker status (open/closed), generator power, generator voltage, generator current, power factor, busbar voltage and  frequency.

The standard Mega-Guard PMS is very easy to configure during installation. A user friendly menu driven user interface is available on the graphic display of the PMS. Parameters such as generator power, number of generators, position of bus tie breaker, busbar nominal voltage, alarm limits, diesel/shaft/shore generator etc. can easily be filled in.

The Mega-Guard PMS can be extended with:

  • Safety system for diesel engine.
  • Check synchronizer with back-up measurement of kW, V, A, Hz and Cos φ.
  • Analog control for frequency and voltage.

System lay-out

Rear view PMS Operator PanelThe Mega-Guard PMS is consists of three items for each generator set:

  • PMS Operator Panel Size: 144x144x55mm (WxHxD) for flush panel mounting.
  • PMS I/O Module Size: 127x198x29mm (WxHxD) for Din rail mounting.
  • I/O Cable in between PMS Operator Panel and PMS I/O Module with a length of 3 or 5 meter.

The PMS Operator Panel is flush mounted in the front door of the switchboard and contains a user-friendly graphic display for read-out of power plant parameters and 12 pushbuttons with lamp indicators for operation of the generator set. The PMS I/O Module is DIN rail mounted inside the switchboard and contains inputs and outputs to connect to diesel engine, generator, busbar and main circuit breaker. The I/O Cable inter-connects the PMS Operator Panel and the PMS I/O Module.

The PMS can be extended with a 24 channel Mixed I/O Module which support the following functions:

  • Safety system for diesel engine with 4 monitored digital inputs and 1 shutdown relay output.
  • Analog control for voltage and frequency: 4 analog outputs 4-20mA.

PMS Operator Panel

The PMS Operator Panel is installed in the front door of the switchboard at each generator section. The Operator Panel provides an user-friendly interface for operation and monitoring of the generator set. The PMS Operator Panel is equipped with built-in Control Processor function and executing power management functions. The PMS Operator Panel is delivered with a graphic LCD display which provides the following information:

  • Generator power
  • Generator voltage
  • Busbar voltage
  • Frequency
  • Cos φ
  • Breaker status
  • System status
  • Alarm description

In addition the PMS Operator Panel is equipped with the following operator pushbuttons with lamps:

  • Auto / manual
  • Start / stop
  • Run
  • Open / close
  • Increase / decrease
  • 1st / 2nd standby                                                                     
  • Menu
  • Alarm

The rear side of the PMS Operator Panel is equipped with terminal strips and connectors as follows:

  • Redundant Ethernet link for communication to other PMS Operator Panels and (when installed) to Mega-Guard Operator Workstations.
  • Power supply input 19~32VDC.
  • System fail output.
  • USB port for memory stick to up-/download an application program.
  • RS485 MODBUS slave communication port.
  • I/O bus connector for connection of I/O Cable.

PMS I/O Module

PMS I/O ModuleThe PMS I/O Module is installed inside the main switchboard at each generator section. I/O signals from generator, busbar, circuit breaker and engine are directly connected to this I/O Module.

The PMS I/O Module  is equipped with a controller which executes generator control functions and the I/O Module communicates with the PMS Operator Panel. The I/O Module can also be delivered as an independent Check synchronizer.

The PMS I/O Module has the following inputs and outputs:

  • 3 phase busbar voltage (0~690VAC)
  • 3 phase generator voltage (0~690VAC)
  • 3 phase generator current (0~5A)
  • Relay outputs (6):
    • CB close / open
    • Engine start / stop
    • Engine increase / decrease speed
  • Digital inputs (6):
    • CB status
    • Engine running
    • Engine start fail
    • Ready to start
    • SWBD / PMS select
    • Engine remote control
  • Relay outputs (8) free configurable functions:
    • Consumer block accept (1~8)
    • Preferential trip (1~8)
    • Shutdown
    • CB abnormal trip
    • CB auto sync fail
    • AVR increase voltage
    • AVR decrease voltage
    • Frequency alarm high / low
    • Voltage alarm high / low
    • Reverse power trip alarm
  • Digital inputs (8) free configurable functions:
    • Consumer block request (1~8)                       
    • Safety system shutdown
    • Bus tie closed
    • CB open all generators
    • CB reverse power trip
    • CB short circuit trip

Sales and service

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Contact information

Praxis Automation Technology
Zijldijk 24A,
2352 AB Leiderdorp
The Netherlands

+31 (0)71 5255 353

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