Distribution Management System (DMS)

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A Distribution Management System is a computer software designed to monitor and control the operations of entire power distribution network reliably and efficiently. In a smart grid, the continuous monitoring and control of power distribution is essential for managing the power system resources.

What is Distribution Management System?

In the context of smart grid, a distribution management system (DMS) is a computer software or a collection of applications which are designed and used for monitoring, controlling, and optimizing the operations of a power distribution system.

The DMS is integrated into the power distribution system to improve the reliability and efficiency of electricity delivery from distribution substations to consumers. It performs several important functions in the distribution network such as real-time monitoring, data analysis, fault identification, load balancing, voltage regulation, etc. All these functions are directly and indirectly responsible for improving reliability and efficiency of the distribution system.

Why Do We Need a Distribution Management System?

In a smart grid, the following are some major needs for integrating a distribution management system into the electrical distribution network −

Reduce the Duration of Power Outages

A distribution management system continuously monitors the distribution network. If there is any fault or abnormal condition, it rapidly detects it and isolates from the healthy part of the distribution network.

The DMS employes several advanced fault detection algorithms to determine the severity and exact location of the fault within the distribution network. This allows the maintenance team for faster reaching to the fault location and reduce the power outage duration by isolating the affected part of the network and reroute the power to rest areas.

Enhance the Speed and Accuracy of Power Outage Predictions

The distribution management system monitors the distribution network in real time to assess its performance and conditions, and the related data is stored in a database. This historical data is analyzed in the DMS to predict the potential issues and power outages under different weather and load conditions.

The analytical tools used in the DMS to predicate the power outages use the patterns and trends of the historical data and it results in faster and more accurate predictions of the power outages.

Reduce the Crew Patrol and Drive Times in Locating the Faults

The conventional methods of locating faults in the distribution network involve lengthy field crew patrols which are highly time consuming. But the distribution management system collects the real-time data from sensors placed across the entire distribution network and analyzes this data to determine the exact location of the fault in the network.

Using this information, the maintenance team can directly reach to location of the fault. Hence, the DMS significantly reduces the patrolling time and also the cost of operation and maintenance.

Improve Operational Efficiency of Distribution Network

The operational efficiency of a distribution network is dependent on load conditions, voltage regulation, energy losses, and many other factors. DMS provides facilities to continuously monitor and assess all these factors and the overall performance of the distribution network.

If there is need to optimize any of these network parameters, the DMS notifies the control room operators or sends the command to the control system automatically. This optimized operation of the distribution network reduces the wastage of energy in the network itself and improves the operational efficiency of the distribution network.

Determine the Crew Resources Needed to Achieve Restoration of Outages

A distribution management system is also capable in determining the nature and severity of the fault occurred in the distribution network. This allows maintenance team to determine the crew resources like number of crew members, types of instruments, etc. required for effective restoration of outages.

Enhanced Customer Satisfaction

For any power distribution company, customer satisfaction is on the top. The distribution management system provides numerous ways through which the utility companies can enhance the consumer satisfaction.

Some of major points are explained here −

• DMS improves the communication between consumers and distribution companies. It uses interactive voice response or other mobile technologies to communicate the information about outage status, estimated restoration time, etc. through calls or text messages.
• DMS allows utility companies to estimate the restoration time more accurately and inform the consumers for when power will be restored. This improves the overall customer satisfaction.
• DMS also maintains a detailed record of parts of the distribution network affected by the power outages. This helps in predictive maintenance and prevention of repeated outages. Hence, DMS also improves the service reliability and thus the consumer satisfaction.

Functions of Distribution Management System

A typical distribution management system (DMS) performs the following important functions −

Network Connectivity Analysis (NCA)

The distribution management system creates a detailed model of the electrical distribution network and shows its different components and their interconnections. The network connectivity analysis helps the distribution system operators to locate the component very easily. It also helps in understanding how different components interact with each other in the network.

Determine the Operating State of the Distribution Network

The distribution management system also assists the system operators to know the operating state of the distribution network whether it is in radial node loops or parallel in the network.

Switching Schedule and Safety Management

In a distribution network, the switching schedule is prepared by the control engineers. This schedule is important for managing the opening and closing of the switching devices to isolate and make safe a part of the network before maintenance work is performed. This schedule is then validated by the DMS using its network model.

DMS also performs safety management so that all the maintenance related tasks are carried out without any danger to operating personnel and equipment.

Load Shedding Application (LSA)

Another important function that the distribution management system performs is the automated load shedding. In a distribution network, load shedding is performed to prevent overloading of the network and ensure the network stability during peak demand period.

The load shedding application of the distribution management system identifies the non-essential loads and temporarily disconnects them from the network to prevent overloading on the system, equipment damage, power outages, and blackouts.

Fault Management and System Restoration (FMSR)

The distribution management system (DMS) also performs the job of fault management and system restoration. Under FMSR, the DMS is responsible for detecting and isolating the faults in the distribution network and system restoration as soon as possible.

The fault management and system restoration function of the DMS rapidly detect the fault occurred in the network and determine its location. It also isolates the affected part to reduce the impact on the rest of the network. Finally, it restores the service in unaffected areas to improve the reliability of the distribution system.

State Estimation (SE)

State estimation is another essential function that a distribution management system performs. It is meant for providing a reliable estimate of the system voltage in the distribution network.

For state estimation of the distribution network, the DMS uses data from sensors and smart meters and utilizes this data to estimate the electrical states of the network like voltages, power flow, etc.

State estimation helps the system operators to predict potential issues in the network and prevent them to optimize the networks reliability and overall performance.

Load Flow Application (LFA)

Load flow analysis is also one of the main functions of a distribution management system. In a DMS, the load flow application is provided to analyze the power distribution within the network under its normal operating conditions.

It performs power flow study of the distribution network to calculate voltages, power flows, and energy losses within the network and provides a detailed report on performance of the network.

Using load flow application, the operators can plan the efficient power delivery and optimize the network performance.

Load Balancing Through Feeder Reconfiguration

The distribution management system also performs the load balancing within the distribution network. This function is performed by the DMS through feeder reconfiguration in which the configuration of the distribution network is adjusted to distribute the load among all feeders evenly.

This function of the DMS prevents the overload condition of feeders and improves the voltage stability in the network.

Distribution Load Forecasting (DLF)

The distribution management system continuously monitors the distribution network and collects the data. The DMS analyzes this data to predict electricity demand in advance.

This function of the DMS helps the operators to accurately forecast the load demand and plan the power distribution accordingly.

Components of Distribution Management System

The block diagram of a distribution management system (DMS) used in a smart grid is shown in the following figure.

From the block diagram, it can be seen that the DMS consists of several components which are explained here −

Advanced Metering Infrastructure (AMI)

Advanced metering infrastructure or AMI is a component in a distribution management system that consists of smart meters, sensors, communication network, data management systems, and many other smart electronic devices.

AMI provides two-way communication between consumers and power distribution companies. The primary function of AMI is to collect the real-time data of power distribution and transfer to a control center.

Advanced Distribution Applications (ADAs)

These are computer software designed to perform the optimization of distribution network. The advanced distribution applications provide capabilities to manage and control the operations of the distribution network.

These applications provide the following main functionalities −

• Voltage and reactive power control and optimization
• Fault identification, isolation, and service restoration
• Balance between supply and demand
• Predication of future demand of electricity
• Management and control of distributed energy resources, etc.

Geographic Information System (GIS)

GIS or geographical information system is equipped into the distribution management system to provide visual representation of the distribution network. The GIS integrated with the DMS helps in determining the location of the network equipment and customers.

Distribution SCADA

Supervisory Control and Data Acquisition (SCADA) is also an important component of the distribution management system. It provides real-time monitoring and control facilities of the distribution network. It also enables the operators to manage and control the distribution network devices from a remote location.

The distribution SCADA uses remote terminal units (RTUs) and other smart electronic devices to collect real-time data from the distribution network and communicate this collected data to a SCADA master station, where it is processed to determine the networks status and conditions.

The distribution SCADA helps the utility companies to efficiently manage the distribution networks.

Energy Management System (EMS)

EMS or Energy Management System is a component provided in a distribution management system to manage and control the power generation, distribution, and storage in the distribution network.

EMS is responsible for controlling the power generation, monitoring the power flow in distribution network, and predicting the energy demand. Therefore, EMS optimizes the overall performance of the distribution system.

Outage Management System (OMS)

Outage management system is a component of the distribution management system that manages and reduces power outages. It collects data from AMI, GIS, and SCADA, and predicts the potential issues in the network and restores the service as soon as possible. Therefore, OMS reduces the outages duration and improve the consumer satisfaction.

Advantages of Distribution Management System

In a smart grid, the following are some major advantages of the distribution management system (DMS) −

• Distribution management system reduces the frequency and duration of power outages and thus improves the reliability of the distribution network.
• DMS reduces the energy losses in the distribution network and hence optimizes the network operations.
• DMS provides real-time monitoring and control facilities of the distribution network which helps better management of the network.
• DMS enables two-way communication between utilities and consumers. This helps in enhancing the customer satisfaction.

Disadvantages of Distribution Management System

Distribution management system (DMS) also has some down sides which are listed here −

• The initial cost required for implementation of distribution management system is high.
• The implementation and operation of a distribution management system is a technology intensive complex task and requires skilled personnel.
• DMS involves the use of digital communication which highly vulnerable to cyberattacks.

Conclusion

In a smart grid, the distribution management system is used to optimize the overall performance of the distribution network.

The distribution management system (DMS) is a collection of computer applications designed to manage and control the distribution network. Its key role in the smart grid is to make the power supply stable and reliable at the distribution level and to improve the customer satisfaction.