Distribution Grid Automation

The same is true for central systems. Systems at medium voltage (MV) or voltage (LV) levels; different designs such as radial, open ring and unthinkable. Each one is determined according to its group.

System systems feeding industrial and commercial loads should be automated in a timely manner. The distribution system reduces the segregation process, causing it to be bred to be passed through the system, able to be in a position to take advantage of the system made up of defective parts.

This white paper explains the basics of electrical distribution systems using PLCs, SCADAs, IEDs and RTUs…

Ongoing Insufficiencies of Existing Grids

When we look at today's network system in general, it is formed by connecting long transmission lines of large and various power plants. In the event of a malfunction that may occur at any point of these lines, the entire network is faced with the danger of collapse.

  • Difficulty of reactive power control due to bidirectional energy flow
  • Undesirable voltage changes due to changing active and reactive power
  • Flicker and harmonic production is not within the desired limits.
  • Short-circuit current limits and thermal endurance capacities of existing network elements
  • The increase in the effects of short-circuit currents according to the connection groups of the transformers on the network and the constant change of the relay selection criteria
  • The network range is not within the limit values in temporary situations such as switching events and instantaneous activation events.

We can list the main advantages of EUTO smart grid products as follows:

  • It will allow remote and instantaneous monitoring and control of energy consumption. In this way, the need for human resources for the provision of user data in conventional networks will be eliminated.
  • It will ensure the improvement and development of the transmission and distribution infrastructure. He/she will be able to detect and correct emergencies before they occur, or heal himself/herself in a way that prevents them from occurring.
  • Electricity consumption rates will be compared in real time at certain points, reducing the electricity loss-leakage rate.
  • Smart grids will enable the distribution of electricity generation and distribution structure. In this way, a problem that may arise at any point of the network related to generation and distribution will be prevented from affecting all users in general, as in conventional networks.
  • It will offer more network management opportunities to distribution and transmission companies. Electronic communication will be provided with subscribers, and commercial losses will be reduced.
  • It will enable the realization of smart home automation projects (refrigerator, air conditioner, etc.), allowing the consumer to play their own role in the optimization of the business in the electrical system.
  • Consumers can purchase electricity with more dynamic pricing. 20-25% savings will be achieved in electricity costs.
  • It will be ensured that renewable energy sources can be integrated into the interconnected system more easily and quickly.
  • It will create a solid infrastructure for electric vehicles. In addition to low usage costs, it will also provide great convenience to the production management system. Most importantly, the existing capacity will be used more effectively and accurately.

Distribution System Automation

Imagine the hassle and confusion for the operator due to the large number of interconnected cables and gauges. Also, don't forget the hassle and time spent commissioning and testing the system. On the other hand, the load is constantly increasing and may change in nature, causing a distribution system redesign by adding new equipment or making changes to the wiring system that may be difficult to implement.

To mitigate these difficulties, each distribution board is equipped with a programmable logic controller (PLC) to perform the necessary control functions, and a user interface workstation is designated at each location. The workstation has the ability to process the data collected from all measurement points in the building with communication cards over communication networks. 

 It provides information on data processing, health, energy management system (EMS), economic distribution, energy interconnect pricing, and other useful applications the workstation is programmed to perform. Information about system status can be sent to the PLC to execute relevant control commands, while other information is used for system planning, maintenance and operation.

This system with high data collection and reporting requirements (but with limited control) is defined as SCADA.

The SCADA system can be easily adapted to any change in the field of application, as it can be integrated with other systems, for example the protection system.

Advantages of SCADA Systems

  • It is easy to self-diagnosis and maintenance.

  • Ability to implement arithmetic functions: Easy to program and reprogram.

  • There is the possibility of communication with other controllers or the main host.

  • PLCs have the ability to switch from simple control to more complex schemes as proportional/integrated/derivative (PID) control.

  • Industrial plant SCADA can be viewed as a distributed control system (DCS).

  • It has a graphical user interface (GUI) and a visual display of system status.

Instrumentation (Sensors)

This component refers to devices used to monitor certain parameters, such as sensors, and devices used to control certain modules, such as actuators. Generally, these devices are connected to equipment or machines that are monitored or controlled by the SCADA system.

Their main function is to convert parameters from physical form to electrical form as continuous (analog) or discrete (digital) signals that can be read by remote station equipment (RTUs or PLCs).

Remote Stations (RTU/PLC)

Monitored and controlled plant-connected measuring devices (first component) are interfaced to the remote station. The functions of remote stations are:

  1. Data collection from different devices in the monitored and controlled facility;
  2. Memorizing the collected data and waiting for a request from the base station (master terminal unit [MTU]) to transmit the data;
  3. Receiving data and control signals from MTU and transmitting control signals to plant devices.

The remote station is either RTU or PLC. RTU is effectively used in difficult communication situation.

The RTU has digital/analog inputs and outputs with light-emitting diode (LED) indication (selectable per channel), optically isolated for surge protection, and also short-circuit protected. On the other hand, PLC is usually expected to be already present in plant processes, so its use in SCADA systems is of great importance.

Communication Networks 

Geographically dispersed RTUs connect to the MTU through various communication channels, including radio links, leased lines, and fiber optics. The design of both RTUs and MTU is greatly affected by availability limitation and high cost of communication channels.

The hardware and software design of both the MTU and the RTUs must ensure that information is transferred correctly from the RTUs to the MTU and vice versa and is unaffected by random noise in the communication channel.

The configuration of the communication system depends on:

  1. Number and location of RTUs,
  2. Number of points in RTUs and required update rates,
  3. Communications equipment, techniques and facilities available.

Main Terminal Unit (MTU)

It is also called “central control station or central station or SCADA manager”. It is considered the heart of the system, in which its main functions are located:

  1. To communicate, collect data, store information, send information to other systems;
  2. Processing of data collected by remote stations to create the necessary actions;
  3. Interfacing with operators mainly through monitors and printers.