Wide Area Monitoring System (WAMS)

Quiz

In recent years, the electric grid has undergone a significant change to meet the increasing demand of electricity and need to develop a reliable and efficient power system. During this evolution of electric grid, several technologies are integrated into the grid and named it as smart grid. One such technology of smart grid is Wide Area Monitoring (WAM) which is implemented to improve the reliability, efficiency, resiliency, and sustainability of the grid.

The primary function wide area monitoring system or WAMS is to modernize the electric grid and to avoid power outages and blackouts. In this chapter, we will learn about WAMS in detail along with its components and advantages.

What is Wide Area Monitoring System?

Wide Area Monitor (WAM) system is an advanced technology used to upgrade the existing electric grid to the smart grid. It modernizes the delivery system of electricity and avoid blackouts and severe outages.

WAM is basically a synchro-phasor technology that employes synchronous measurement to monitor and evaluate the state of the electric grid. It is called wide area monitoring because it functions over a wide geographical area.

The WAM system uses smart sensors to collect time-synchronized data about the grid operations. For this purpose, it uses high-speed communication system that can report power system data 25-50 times in a second.

Why Do We Need the Wide Area Monitoring System?

In smart grids, the increasing technical complexity in interconnecting multiple grids together arose the need for wide area monitoring system. This is because, the traditional monitoring technologies are based on localized and delayed data communication, which may lead inefficiencies in modern grid management.

The wide area monitoring system is employed in smart grid for the following reasons −

It is fast and efficient in detecting and responding to faults and disturbances. Thus, it results in improved reliability.
It provides real-time data about grid operations and helps in better management of the grid.
It reduces the impact of faults and disturbances on the system by rapidly detecting and isolating them.
It improves the sustainability of the grid through the integration of renewable energy resources.

The Main Components of WAMS

The main components of the wide area monitoring system (WAMS) are shown in the following block diagram −

The functions of the components of wide area monitoring system are explained here −

Phasor Measurement Unit (PMU)

It is a device used in wide area monitoring system to measure the electrical waves flowing in the grid and to provide their data like voltage, current, and frequency in real-time. Thus, PMUs are used to provide the time-based representation of power flow studies by collecting power flow data from the grid. Therefore, the output of PMUs is termed as Time Stamped : Grid Snapshot of the power grid. PMUs consist of GPS receivers and microprocessor-based devices like relays, fault recorders, etc. and a communication system for transferring he PMU data to phasor data concentrator.

Phasor Data Concentrator (PDC)

PDC are the systems that used to collect the electrical parameters measured by a number of PMUs. It is responsible for collecting vast amount of phasor data captured by PMUs, correlate them and feed as a single stream to other applications.

Data Historians

These are the systems provided in WAMS to obtain the synchro-phasor data and to keep their alignment in a proper sequence.

Data Visualization Applications

These are the graphical interface-based applications used for showing data to control room operators to identify the grid conditions and issues.

Communication System

It is the major backbone of the wide area monitoring system. As the PMUs are distributed across the grid over a wide area for real-time monitoring. It consists of optical fiber links to connect these PMUs to the substation switch or router.

Control Center

These are the facilities that have advanced software and tools to analyze the grid and take the remedial actions.

Measurement in WAM System

Wide area monitoring system utilizes a GPS satellite signal for time-synchronization of data from the phasor measurement units (PMUs) placed across the grid. This real-time phasor data is then sent to control center that provides dynamic information on the grid conditions. This helps the control room operators to take corrective actions to improve the grid reliability.

This grid data can also be streamed to a central control center from different substations in the grid. At the central control center, this data is evaluated to provide a precise picture of the grid operations.

How Does a WAM System Work?

The detailed working of a wide area monitoring system employed in smart grid is explained below −

Firstly, the PMUs installed across the entire grid measure the electrical data and time-synchronize these data using a GPS satellite signal.
The collected data is then transmitted to phasor data concentrator (PDC) through a secure communication network, where correlation of the data takes place.
The correlated data is next fed to WAM applications to process and analyze to evaluate the real-time condition of the grid.
In the next step, the visualization applications show the grid conditions and potential issues in the grid based on which the control room operators make the decisions and take remedial actions.

This is how a typical wide area monitoring system works in a smart grid.

Advantages of WAM System

The following are some major advantages of wide area monitoring system in smart grid −

Through real-time monitoring, the wide area monitoring system provides the up-to-date information about the grid operations and conditions.
WAM system improves the stability of the electric grid by rapidly detecting and isolating the faults and disturbances.
WAM system helps in the faster and accurate fault detection through high-speed communication.
Wide area monitoring system enables grid operators to better manage the resources and improve the overall efficiency of the system.

Challenges of WAM System

The major challenges in the implementation of wide area monitoring system in smart grid are listed below −

The implementation and deployment of wide area monitoring system is a cost intensive task and requires a high investment.
There are also issues with availability and setting up of high-speed communication infrastructure for WAM system.
The implementation of WAM system in smart grid needs setting up of standards and compliances.
Selecting most appropriate locations for installing PMUs is also a big challenge in WAM system.
WAM system is also vulnerable to cyber-security issues.
WAM system requires advanced tools for in-depth analysis of grid data which is a complex technology intensive task.
It is also needed to develop better visualization applications for system operators.

Applications of WAM System

The wide area monitoring system is one of the key components in smart grid technology. Its primary function in the grid is to monitor and show the grid status in real-time. In smart grid, the following some key uses of WAM system −

Monitor the grid conditions and stabilize the operations.
Detect and inform the grid operators about potential issues.
Rapid detection and isolation of faults.
Load balancing to distribute the load evenly across the grid.
Managing the renewable energy resources integrated into the grid.

Conclusion

The WAM system is one of the crucial components in a smart grid as it provides real-time monitoring facility of the grid and reduces the outages and blackouts.

The primary aim of using WAM system in smart grid is to collect real-time data from grid that provides insights about status of the grid and helps in improving reliability, efficiency, and sustainability of the grid. It stabilizes the power system and optimizes the resource utilization which are important parameters to achieve a reliable smart grid.

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