SCADA and Its Application in Electrical Power Systems

In today’s digital world, we are looking for new opportunities to automate and accelerate our workflows and industrial processes. Since the invention of the computer and the internet, machines begin to integrate computing technologies within the system. This advancement in conventional systems started the new age of the industrial revolution. And like any other system, the power system is no exception.

Power Systems have evolved according to the needs of investors, consumers, and operators over the past decades. Enterprise Resource Planning Solutions has led power systems to automate. And so, power systems began to incorporate the SCADA system in the late twentieth century. Before we know what SCADA systems are, we need to consider the history first.

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Types of Sub

History of SCADA system

In the early years when electric power systems began developing, electricity generation plants were only associated with their respective local loads. If anything failed in the whole linearly connected system, which could include subsystems like generating plant, power lines, connections, then the lights would be out. Customers had not yet adapted to depend on electricity. Outages, whether routine or emergency, were taken as a matter of course. As reliance on electricity grew, so did the need to find ways to improve reliability.

Generating stations and power lines were interconnected to provide redundancy. As the system expanded and began to scale out in size, it became harder to manage. Solutions were needed to face the challenges of controlling equipment over long distances. To overcome this, operating personnel were often stationed at the important points in this grid system so that they could monitor and quickly respond to any problems that might arise due to any fault or failure. They would communicate with central electricity dispatchers, often employing telephone, to keep them informed about the condition of the system.

Many manufacturing floors, remote sites, and industrial plants relied on personnel to monitor equipment and manually control through mechanical push buttons and analog dials. As the demand for reliable electricity grew even more and as labor became a significant part of the cost of providing electricity, technologies such as SCADA were developed which allow remote monitoring and control of the system’s key parameters.

What is SCADA?

SCADA stands for Supervisory Control And Data Acquisition. SCADA is a system of different hardware and software elements that come together to enable a plant or facility operator to supervise and control processes.

By Daniele Pugliesi — Own work, CC BY-SA 3.0, Link

Supervisory Control is a general term for a high-level of overall control of many individual controllers or multiple control loops. It gives the operations supervisor an overview of the plant process and permits integration of operation between low-level controllers.

Data acquisition is the process of sampling signals by measuring a physical property of the real world in the form of signals and converting it from analog waveform into digital numeric values so that it can be processed by computing machines.

Key features

Some of the key features of the SCADA system are mentioned below.

  • Supervision:

Computers process the data and let personnel in charge to oversee and direct the status of the power system using the acquired data. Personnel in charge were often operators and engineers who monitor the information remotely or locally. Now, the master station is tasked to supervise most of the system.

  • Control:

Control in SCADA refers to sending command messages to a device to operate the Instrumentation and Controls system (I&C) and power-system devices. Conventionally, SCADA relies on human managers to initiate command from an operator console on the master computer. Field personnel can also control machines using front panels.

  • Data collection:

Instead of collecting data and filling datasheets by hand, SCADA automatically compiles information in real-time. SCADA gathers data from hundreds or even thousands of sensors at a given time. It also generates backlogs for later analysis.

  • Data communication:

SCADA delivers information to a central hub. A communication network transport all the data gathered from sensors. Earlier systems had radio or modem. Today, SCADA data is transferred over internet protocol (IP) and Ethernet.

  • Data presentation:

SCADA interacts with human operators through work-station computers that deploy Human Machine Interface (HMI). The master station presents a widespread view of the whole system and alerts the operator by visual display or alarm sound.

Components and its functions

By deramsey — Own work, CC BY-SA 4.0, Link

SCADA system comprises of Sensors, Conversion units, Communication network, Master unit and Remote communication server (RCS).

To learn the detail of each SCADA components , then click on “SCADA Components and its functions”.

Applications of SCADA

SCADA system application sectors

Commonly SCADA systems are used when a need arises to automate complex processes where human control is not feasible. In power system specifically, this can include

  1. The system needs an uninterrupted power supply and a protected environment
  2. We would need to know the status of a complex power system in real-time
  3. We would need to monitor and control system that are in remote areas

The power generation, transmission and distribution sectors, supervision, monitoring, and control are the main aspects in all these areas. Therefore, the SCADA implementation of power system improves the overall efficiency of the system for optimizing, supervising, and controlling the generation, transmission & distribution systems. SCADA function in the power system network offers greater system reliability and stability for integrated grid operation.

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SCADA for power generating stations:

Bringing an optimal solution for each process to involve in power generation operation is flexible with advanced control structures. With the use of PLCs and powerful bus communication links along with SCADA software and hardware in generating stations, it supervises several operations including protection, monitoring, and controlling. To provide reliable energy, to minimize operational costs, and to preserve capital investment, the SCADA system is taken as seriously in generating stations.

The highlighted functions of SCADA in power plants include:

  • Continuous monitoring of speed and frequency of electrical machines
  • Geographical monitoring of coal delivery and water treatment processes
  • Electricity generation operations planning
  • Control of active and reactive power
  • Boiler and Turbine protection and their condition in case of thermal plant
  • Monitoring of renewable energy farms and load dispatch planning
  • Load scheduling
  • Historical data processing of all generation related parameters
  • Supervising the status of circuit breakers, protective relays, and other safety equipment
  • Power apparatus health monitor
  • The sequence of events recording

Balance of Plant (BOP) are auxiliary systems and supporting components needed to run the main generating unit and deliver energy. SCADA system is also highly effective in the supervision of the Balance of Plant.

  • SCADA for power transmission system:

Transmission line corresponding circuit model parameters are often in error as compared to values measured by the SCADA system. Without a SCADA system, these errors cause the economic dispatch to be erroneous, and hence, lead to increased costs or incorrect billing. These errors could also affect state estimator analysis, contingency analysis, short circuit analysis, distance relaying, machine stability calculations, and transmission planning in case of expansion. Therefore, SCADA integration into the transmission system is significantly considered.

Some main functions of SCADA in electric transmission system are as follows:

  • Re-routing services for station maintenance
  • Service restoration
  • Protective relay interface/interaction
  • Voltage regulation management
  • Load tap changer control
  • Transformer management
  • Real-time modeling
  • Automatic circuit isolation control and interactive switch control display
  • Interface real-time single-line displays
  • On-line operation and maintenance logs
  • Automatic system diagnostics by using system-defined controller alarms (alarm management)

We wrote another article on The Importance of Equipment Maintenance Plan for Electrical Power Systems. Have a look at it if you want to grab information about equipment maintenance plan.

  • SCADA for power distribution system:

The power distribution system deals with the dispersal of electricity from distribution substations to the loads. Many utility companies depend on manual labor to perform the distribution tasks like interrupting the power to loads, hourly checking of key metrics, fault diagnosis, etc. SCADA implementation to the power distribution not only reduces the manual labor operation and its cost but facilitates smooth processes by reducing disruptions.

SCADA system gathers the data from various electrical substations and correspondingly process it. PLCs in substations continuously monitor the substation components and corresponding transmits that to the central system.

It is in charge of:

  • Improving efficiency by maintaining a tolerable range of power factor
  • Limiting peak power demand
  • Trending and alarming the operators by identifying the problem spot
  • Historian data and viewing that from remote and barely inaccessible locations
  • Quick response to customer service interruptions
  • Feeder automation and Load Sectionalizer
  • Provide the ability to over-ride automatic control of capacitor banks
  • Automated meter reading
  • Circuit breaker control, lockout, and interlocking
  • Continuous monitoring and controlling of various electrical parameters in both normal and abnormal conditions which may affect the quality like harmonic distortions

Advantages of SCADA

SCADA systems are an extremely advantageous way to run and monitor processes. They are great for small applications, such as climate control. They can also be effectively used in large applications such as monitoring and controlling a nuclear power plant or mass transit system.

  • Optimizing performance:

SCADA systems minimize errors by accurately measuring data and increasing the overall efficiency of the system.

  • Reliability and robustness:

The specific development of SCADA is performed within a well-established framework that enhances reliability and robustness where power requirement is crucial.

  • Maximize productivity:

The specific development of SCADA is performed within a well-established framework that enhances reliability and robustness where power requirement is crucial.

  • Improve quality:

Analyzes and controls the quality of the produced electric energy profile using standard SCADA functionality.

  • Reduce operating and maintenance costs:

Less personnel and trips are required to monitor field gear in remote locations, this reduces maintenance and training costs.

  • Integrate with business systems:

A SCADA system can be easily integrated with the business systems, leading to increased production and profitability.

Conclusion

SCADA system can be implemented on a large scale in power systems so as to increase their performance, reliability, and durability. Data acquisition and monitoring can be very convenient and accurate if power systems are upgraded to SCADA. Now, electrical systems are extremely efficient and intelligent to monitor and control all of the involved operations and procedures and it has become possible only because of technological advancements. So we can conclude that it’s essential for the power sector to optimize their systems as per the requirements of the technical changes.

Hiring a professional electrical engineer to conduct an Arc Flash Analysis and Short Circuit Study is a great way to ensure the safety of your facility and workers against unwanted incidents.

AllumiaX, LLC is one of the leading providers of Power System Studies in the northwest. Our matchless services and expertise focus on providing adequate analysis on Arc Flash, Transient Stability, Load Flow, Snubber Circuit, Short Circuit, Coordination, Ground Grid, and Power Quality.

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About The Author

Abdur Rehman is a professional electrical engineer with more than eight years of experience working with equipment from 208V to 115kV in both the Utility and Industrial & Commercial space. He has a particular focus on Power Systems Protection & Engineering Studies.

Abdur Rehman is the CEO and co-founder of allumiax.com and creator of GeneralPAC by AllumiaX. He has been actively involved in various roles in the IEEE Seattle Section, IEEE PES Seattle, IEEE Region 6, and IEEE MGA.

Leaders in Industrial & Commercial Power Systems Engineering