SCADA Remote Terminal Units

Intelligent RTUs

Many utilities continue to respond to pressing requirements to replace existing SCADA remote terminal units, without initial consideration to move towards full substation automation installations.

Again, Callisto^nx is able to effectively respond to such retrofit requirements within a substation, and still maintain a smooth upgrade to a full substation automation system should the utility requirements develop.

Equally, with its small footprint, Callisto^nx intelligent remote terminal units are able to easily replace existing legacy RTUs that do not incorporate the range of system functions, intelligence and overall capabilities of Callisto^nx.

Whatever your remote terminal unit retrofit needs, Remsdaq is ready to respond with a Callisto^nx solution that incorporates an unsurpassed solution base to meet current and emerging system requirements.

Retrofit Solutions

Callisto^nx, in conjunction with its actuator controller interface provides an ideal solution for retrofitting legacy distribution switchgear as an alternative to switchgear replacement. Remsdaq is able to offer switch actuators that enable virtually any type of manually operated switch to be incorporated in a distribution automation system.

The identical Callisto^nx system facilities, as provided for the most sophisticated substation automation system are incorporated, so that the utility is able to benefit from the advanced protection and protection related applications, extensive metering and measurement capabilities, PILoT^nxprogrammable logic, CaSE^nx software configuration tool, View^nx web browser and Touch^nx local user interface to meet overall system demands.

SCADA System Components

There are four principle components within a SCADA system:

• Sensors
• RTUs
• Master Stations
• Communications Networks

What is a Sensor?

In a SCADA-type installation, the sensor (or transducer) collects and measures data from specific points of an installation (objects) and the systems making up the local installation. Within an electricity substation, sensors can collect and measure data including voltage, frequency, real power (kW) and apparent power (kVA) and power factor. The sensors can be analogue or digital. Analogue sensors can detect continuous changes at a given location. Digital sensors can measure discrete inputs and simple signals (e.g. On/Off).

What is an RTU?

An RTU (remote terminal unit) interfaces the sensors to the SCADA Master Station or Communications Network.

RTUs provide telemetry information and some local control facilities. They differ to Programmable Logic Controllers (PLCs). Both are microprocessor controlled electronic devices. Where they differ is that a PLC is typically used within a factory automation installation (for automated production lines, lighting or HVAC controls) where the PLC is programmed to monitor and control a specific system or component within the installation. An RTU is typically used within a wider geographic area to measure and collect data which is reported to a Master Station.

In addition to analogue and digital inputs, an RTU also has digital outputs which can be used to control various aspects of the installation objects.

What is a Master Station?

A Master Station (also known as a Master Unit) is a supervisory computer system, Human Machine Interface (HMI) or software package. The computer system can consist of a single computer or multiple servers, distributed software applications and disaster recovery sites. The Master Station stores measurement information collected through the RTUs from the sensors and automatically regulates and controls the system.

Communications Networks

Remsdaq RTUs can be used with several electricity supply network configurations:

• At the local substation level including packaged substations, reporting locally through an HMI (human machine interface) or master station.
• Within a network management system (NMS) supporting a smart city.
• Within a distribution management system (DMS) provide SCADA information over a wide geographical area.
• At the utility transmission level within an energy management system (EMS) and smart grid application utilising renewal and alternative energy sources including lithium-ion battery installations for back-up to grid generated power and demand side response (DSR) programs.

Electricity Network Installations

Remsdaq Callisto RTUs are designed and manufactured in the UK and can be configured for a wide range of voltages and applications:

Typical Voltages

• Transmission: Extremely High Voltage (EHV) above 275kV to 400kV
• Primary Distribution: High Voltage (HV) 275kV to 33kV
• Secondary Distribution: Medium Voltage (MV) 33kV to 11kV
• Sub-distribution: Low Voltage (LV) up to 11kV

Typical Applications

• Events recorder
• Power quality monitor
• Digital fault recorder
• Intelligent electronic device
• Plant condition monitor
• Electronic meter
• Data logger
• Trend recorder
• Phase management unit
• Data concentrator
• Communications gateway
• Protocol converter
• LV monitoring

Remsdaq is pleased to assist utilities in deferring capital expenditure related to switchgear replacement and offer the best Callisto^nx solution to meet your application needs.