Smart OCR Protection for Electric Grid

The electrical power system network is prone to failure due to unavoidable fault occurrence in the system. In the recent time, fault occurs in a transmission line of Pakistan and because of this fault, cascading fault occurs in the grid which trigger the blackout in many major cities of the country.

Project Title

Smart OCR Protection for Electric Grid

Project Area of Specialization

Electrical/Electronic Engineering

Project Summary

The electrical power system network is prone to failure due to unavoidable fault occurrence in the system. In the recent time, fault occurs in a transmission line of Pakistan and because of this fault, cascading fault occurs in the grid which trigger the blackout in many major cities of the country. The possibility of fault occurrence increases for a long line and is located in remote location. Hence, one of the most important aspects of the power system is to have an effective protection system. An effective protection system minimizes revenue loss by avoiding disruption of electricity supply and protecting expensive equipment such as generators, switchgear, conductors, condensers, and transformers from damage. For effective protection of the power system, the protection relays must be coordinated effectively and isolate the faulty area with adequate margins without unnecessary time delays .

The conventional electrical grid is protected by non-directional over current relay which detect the fault current and disconnect the faulted branch from the network. However, it is recommended that protection of modern electrical grid through the direction over current relay, which can sense also fault propagation in the network. But the coordination of between the directional relay need to be considered otherwise nuisance tripping will occur in power system.

In this project, directional over current relay-based protection for small scale (3- bus) electrical grid is developed. Grid is supplied with generator and all electrical buses are equipped with two directional over current relay.  MATLAB based algorithm determine the Plug setting and time multiplier setting for relay coordination. The coordination attain from the MATLAB algorithm will be verified through ETAP (industry standard power system simulator). In house directional over current relay is built with the help of raspberry pi, circuit breaker, relay module, current sensor and analog to digital converter. In modern distribution system, system can change the configuration or need to change the configuration due to fault in the system, thus directional over current relay coordination also needs to be updated in real-time.

Project Objectives

As Electrical grid is a huge system. So it is impossible to cover whole of the process as a project. That’s why, we just target on 3-bus mesh Distribution system operated in radial structure. Main objectives of our project are as follows:

1. To develop an algorithm for attaining optimal coordination between the directional over current relay.
2. To build direction over current relay which has capabilities to update protection setting in real time.

Project Implementation Method

The status of directional over current relays is transmitted to MATLAB through communication channel (such as serial communication). The proposed algorithm determines the plug setting and time multiplier setting for all individual relays. The setting are transmitted back to directional over current relay which is based on raspberry pi controller. Raspberry pi continuously monitors the current that is flowing in the network. To validate the system, deliberately fault is created, which increase flow of current in the branch. Once current equal to pick-up current value, timer start, and it will trip the branch to avoid propagation of fault in the network. Similar, after modifying the network structure, MATLAB algorithm will evaluate the need of updating protection setting for update network configuration, if requires than it will attain the new PS and TMS for individual relays.

Benefits of the Project

Smart grid has capability to modify it structure in order to minimize the power loss and avoid overloading of the network, but it can disturb the protection setting. As these OCR relay can be updated online thus it will allow configuration to change in the grid without disturbing the network continuity. These OCR relays avoid nuisance tripping therefore electrical network will become more reliable. Incorporating these relays in the network will provide protective management of electrical network in emergency conditions

Technical Details of Final Deliverable

According to the fact that almost 90% of disturbances occurs at the distribution part, the concept of smart grid first introduces to overcome this problem. In smart grid, disturbance is reduced through network reconfiguration of electrical network. This mean that network reconfiguration is being through the remote-control switches. However, these configurations can disturb the protection scheme of electrical network. In smart grid, protection of the network is implemented through OCR, however the coordination between (primary and backup) relay is imperative. 

Smart grid is the combination of technologies that replace the generation, transmission and distribution process of existing grid system to two-way communication, intelligent devices and single ended supervision. Currently reconfiguration is done only in case of fault. But future is near, it will be done to improve reliability and efficiency of the network. Thus, other technologies in the existing grid also need to be upgraded and become smart to meet the criteria of future grid as we are entering in the era of industry 4.0.

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Energy

Other Industries

Manufacturing

Core Technology

Others

Other Technologies

Clean Tech

Sustainable Development Goals

Industry, Innovation and Infrastructure

Required Resources

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