The data acquisition and monitoring system is an information system that is used to monitor the distribution system in real time. This provides information on the status of the distribution network, as well as controls for circuit breakers and remote-controlled disconnectors (RCD), for example, and for communications with substation and network automatic systems through remote terminal units (RTUs). The main functions of the SCADA system are according to:
•Event data management
•Manager of network switching status
Event data management provides information on safety relay operation, system change condition and detector functioning. Event data management. When event data is paired with a network model, the switching status of the delivery network can be preserved on the system. The SCADA process database provides detailed descriptions for primary and substation equipment only, whereas the distribution system is usually called a condensed schematic view of links between main and remotely controlled switching devices
Operator: Operator who controls the SCADA system and conducts remote-plant monitoring functions.
Human machine interface (HMI): It provides data to an operator and enables the control of inputs in many formats, such as graphics, schemes, windows, menus, contacts, etc.
Master terminal unit (MTU): A control device with the equivalent of a control / slave arrangement. The MTU shows data to the operator via the HMI, collects data from the remote location and sends control signals to the remote location. The transmission rate between MTU and remote location is relatively small and, because of potential interruptions in time or flow, the control method is typically open loop System Structure.
Communications means: Communication between the MTU and remote controllers. The Internet, cable, cable or public telephone networks can be used to communicate.
Remote Terminal Unit (RTU): Acts as an architectural master / slave slave. The system sends control signals and data from these devices to the controlled system and sends them to the MTU. An RTU may be a PLC. The device data rate controlled by RTU is very high and the control method is normally closed.
As stated earlier, the SCADA architecture consists of two levels: The control center master level or client level, and the slave or data server level dealing with controllable processes. Both the software and hardware components of the SCADA architecture are essential. Components of SCADA software include two modules, the Client (master) and the Slave (data server), which are linked by communication network to each other.