SCADA (ENMC or E-SCADA) is Supervisory Control & Data Acquisition System. This deals with two sections.
1)Substation / equipment / process to be monitored and controlled.
2)Network of devices (IEDs, SCADA master / HMI, RTU, etc) that interfaces with substation / equipment / process.
Power distribution to various electrical loads is controlled by the switchgear feeders installed in the substation. Hence IED's (Protection relays / Measurement centers / Instrument transformer, Transducers) and sensors mounted on the switchgear feeders collect various data (e.g. current, voltage, power, status of switchgears etc.) and send to the SCADA master via the device interface network..
RTUs (Remote Telemetry Unit) are also deployed at specific locations in the field to gather the information from various equipment and communicate to SCADA master.
SCADA master collects and processes the data for control and monitoring.
HMI (Human Machine Interface) exchanges data from SCADA master in a predefined presentable format. This consist of information for effective operation control and monitoring.
In short, substation engineer has a constant access to real time information for his analysis and controlling various equipments / process.
Communication network can be through MODEM or dedicated optical fiber / serial port lines. By and large SCADA communication takes place through LAN only.
Most widely used communication network are RS232, RS485 link, Ethernet cable, fiber optic cable etc.
Redundant network ensures interruption free communication, if required.
Communication protocol is based on preset formats and rules to allow SCADA system to send and receive analogue / digital signals.
Most widely used protocols are MODBUS / IEC60870 / IEC61850 standard.
Features of SCADA (ENMC or E-SCADA):
Display of real time data of all substation parameters acquired from protection relays, measurement centers and other intelligent electronic devices (IEDs).
Animated Graphical User Interface (GUI).
Communication with IED's through standard protocols like MODBUS, DNP, and IEC 61850 etc.
Secure Control of switching device.
Display of real time and historical alarms, events and trends.
Report generation.
Waveform capturing and recording of alarms, disturbance and fault conditions.
The Data Acquisition System / ENMC or E-SCADA system comprising an Industrial grade computer, Colour Monitor, Converters and Printer etc. is mounted in a stand-alone panel. The Relays and Measurement Centers are mounted in the respective Control and Relay Panels or Switchgear Cubicles.
