The ISMS is an Integrated Substation Management System for HT – Power circuit applications. It provides measuring facilities for a number of 3phase-4wire system parameters, Digital status monitoring, Analog signal monitoring and controlling of the digital output. The monitored parameters are transferred to the HMI through Ethernet and the data are available in the server for analysis at remote end, through Internet.

The ISMS offers

  •  High accuracy of measurement : 0.5 S Class.
  • Use of 32 bit RISC Processor and Digital Signal Processor (DSP) provide high
    accuracy, fast response and programmability.
  • 8 Channel of Digital Status monitoring
  • 4 Channel of Control Output
  • 2 Channel of Analog signal monitoring
  • Local isolated RS232 communication port for configuration.\
  •  Ethernet communication to the HMI
  • Operates on 240VAC or 110V DC, aux. supply.


Input Specifications

  • System : 3Phase-4wire
  • Input voltage : 110V (Line to Line).
  • Input voltage limits : 77V to 132V (110 -30%, +20%).
  • Input current : 1A or 5A nominal- Factory configured. (request factory for
  • correct configuration).
  • Input current limits : 10mA to 1.2A OR 50mA to 6A (0.01% to 120% of Ib)(Factory configured).
  • Input frequency : 50Hz ± 5Hz.
  • Digital Status : 110V DC from Contact Multiplier
  • Digital Output : Trip & Close of Breaker at 110V DC
  • Analog Input : Battery voltage : 110V DC (Factory configurable), Resistive
  • Input ranging 0 to 3000 Ohms

Output Specifications

  • Energy parameters of 0.5% accuracy
  • Display of the Parameters in 4×20 Display with Backlight
  • Communicate to the HMI through Ethernet
  • LED pulse output for kWh and kVArh calibration.
  • LED indication of the Digital Status for each channel
  • LED indication for the Power supply

Communication interfaces

  • Isolated three wire RS232 interface. This can be used for local configuration of the unit
  • Ethernet communication for transferring the data from the unit to the HMI

Power supply

  • The operating voltage : 110V DC or 240V AC
  • Power consumed : Less than 10W.

Environmental specifications

  • Normal working temperature : 0°C to 50°C.
  • Functional temperature : 0°C to 60°C.
  • Storage temperature : -10°C to 65°C.

Feeder Remote Terminal Unit (FRTU)

The FRTU system should be able to monitor all the sub-station equipment should acquire all parameters in respect of all incoming and outgoing feeders on real- time basis and the status signals of the devices.

The overall system needs planning and execution, forecasting and implementation, maintenance etc.

Energy supply is to be balanced with the load demand continuously under normal and abnormal situations such as loss of generation, equipment failures, Line faults, peak loads, load shedding etc to maintain system stability, reliability and availability.

The application of FRTU principles load to automatic date logging, sub-station level control. Energy management, load forecasting etc. Scheduling eventually to sub-station automation.

The electrical networks are frequently being expanded and reinforced resulting in more complex networks. Hence, energy transportation, monitoring and control to achieve an economical and operational efficiency requires an ongoing penetration of the grid down to the lowest level and implementation of a viable FRTU system is imperative.

The system should be comprehensively self monitored and faults will be immediately indicated to the operator possible before they develop into serious situations. Such faults are recorded as faulty status in a system. The display should cover the status of the entire substation including all switchgear and communication links. Dynamic coloring of SLD with load schedule, power factor, voltage, power etc.

This system is a replacement for SCADA system. In existing SCADA system data collection module is in Linux SBC and SBC sends the data to HMI, HMI uses these data for further process.

In FRTU data collection Module coming under HMI. HMI having separate service for collecting the data from FRTU Unit.

Major modules

  • FRTU Service-To Collect the data from FRTU unit
  • Local HMI-Display the result to end user and display the reports to end user
    • EMS-Energy Management System
    • DO-Digital Output
    • DI-Digital Input
    • AI-Analog Input
  • GPRS Service-To send instantaneous data to Remote HMI
  • GPRS DO Service-To receive control data from Remote HMI

This Software Requirements Specification designed for Radhapuram 110/33-11 kV Substation.