Development of relay test unit
Relays are major component of Electrical Power System Protection Infrastructure. The safety and operation of the system depends on the proper functioning of Relays and hence it requires routine testing of these relays to ensure their reliability. These routine tests are performed by a Relay Testing
2025-06-28 16:32:06 - Adil Khan
Development of relay test unit
Project Area of Specialization Shared EconomyProject SummaryRelays are major component of Electrical Power System Protection Infrastructure. The safety and operation of the system depends on the proper functioning of Relays and hence it requires routine testing of these relays to ensure their reliability. These routine tests are performed by a Relay Testing Unit which injects artificial fault currents in the relay. These Testing Equipment are very expensive and are not assembled locally. A prototype of this equipment has not been developed at undergraduate level, hence this project we will incorporate development of relay testing unit which will test single channel relays including over current relays, earth fault relays and reverse power relays. The testing equipment will be portable and will be accompanied by a user-friendly interface. The testing unit will have built-in measuring equipment which will be controlled by micro processing unit.
Project ObjectivesObjective 1:
The main operation of relays is to measure the ongoing current in the system and issue a trip signal when this current reaches an overload or fault value. During test of these relays, we inject artificial fault currents in the relay to replicate the actual fault relay currents. For the injection of these current, a high current source is required. The first objective will be to design a current source to generate high currents in controlled and safe environment.
Objective 2:
To design a control, measuring and protection system. The control system will control the test current and will perform automatic switching during tests. The measuring system will incorporate different instruments to measure real time currents to give visual realization. The protection system will protect the equipment from in system faults. A clock mechanism will be used to test the time of relay tripping.
Objective 3:
To implement a graphical user interface, a centralized controlling system and a proper casing. The graphical user interface will display readings from measuring instruments, test results and status of equipment. The centralized controlling system consisting of a micro-processor will perform all control operations along with decoding the values of measuring instruments. A proper casing will be provided to the equipment consisting of control buttons and visual displays.
Project Implementation MethodTask 1: Development of a small-scale prototype for high current generation.
Task 2: Development of current source to output high currents. (30A preferably).
Task 3: Develop a control logic and implement the measurement equipment.
Task 4: Incorporate micro-processor and GUI to perform automated task and display measurement and test values.
Task 5: Make casing to implement all above into a single portable and user-friendly unit.
Benefits of the ProjectWith expansion and increased complexity of electrical power systems, periodic testing of electrical relays has become a necessity. With the development of test set following benefits will be achieved.
- The equipment will provide a very cheap alternative for protective equipment testing.
-In most of Engineering Institutes, no such test set is available hence most of students are unable to get familiar with relay testing in their student life. The designed test set will be ideal for In Lab testing of relays and MCBs.
- One of the most important features of the equipment is its capability to test wide range of Miniature Circuit Breakers. MCBs are most common domestically used protection devices. Since there are various brands of MCBs available in market, some of the installed MCBs could be faulty and may cause short circuit fire in case of a fault. At domestic level, there is no device to verify the operation of MCBs. This test set can be used at homes or by vendors to verify the designated operation of MCBs.
-The test set also allows for testing of auxiliary circuits connected to relays, including alarm and indication circuits.
The objective of this project is to create an inexpensive alternative of a relay test set. There are many test-sets available in market, but the most important limitation is their price. There were three main objectives of this project comprising of developing a current source, development of measurement and control system and providing an enclosure to house the equipment. Till now the first two objectives are almost met and the project is capable of testing wide range of single or multipole MCBs with its current injection system, measurement system and interactive interface. The project will be converted into full scale test equipment with rigid enclosure and testing interface comprises of an interactive display and terminals for test current injection. Also, the project will be enhanced to obtain its actual purpose that is testing of wide ranges of relays including overload and short circuit relays (50/51/67)[6]
Relay test set is a very versatile equipment and can be modified to perform wide range of testing which involves secondary injection. This equipment can be modified in in future to test over and under voltage relays (27/59) and over and under frequency relays (81). The equipment can be used in Institutes to enable students to gain first-hand knowledge and experience about the techniques and methods of relay testing employed in field. Also, it can be modified to be used in harsh industrial environment.
| Item Name | Type | No. of Units | Per Unit Cost (in Rs) | Total (in Rs) |
|---|---|---|---|---|
| Total in (Rs) | 70000 | |||
| Variac | Equipment | 1 | 10000 | 10000 |
| Step Down Transformer | Equipment | 1 | 15000 | 15000 |
| Measuring Instrument | Equipment | 1 | 5000 | 5000 |
| Control Equipment | Equipment | 1 | 5000 | 5000 |
| Micro Processor and touch screen Displays | Equipment | 1 | 15000 | 15000 |
| Casing | Equipment | 1 | 10000 | 10000 |
| Auxiliaries | Miscellaneous | 1 | 10000 | 10000 |