Transformer Difference Protection System Commissioning
Introduction
The transformer difference protection system (TDPS), also known as a two winding differential protection scheme, is an important system used for the protection of electrical power transformers. The primary aim of the system is to detect any external faults and internal faults of the transformer and quickly trip off the faulted section. This ensures the safety and operation of the power system is maintained. The TDPS consists of two differential relays installed on the high and low voltage sides of the transformer, which are connected in series.
In order to commission the TDPS, it is essential to verify that it is correctly wired and the settings conform to the intended application. This verification requires the system to be tested step-by-step, while adopting a systematic approach to the commissioning process. This paper aims to discuss the various steps involved in a TDPS commissioning process.
Commissioning Process
The commissioning of the TDPS involves a number of steps, which must be performed in a specific order to ensure the system is correctly wired and functioning as expected. This section will outline the various steps involved in the commissioning process.
1. Verifying the Wiring
The first step in TDPS commissioning is to ensure that all of the components are wired correctly. This includes verifying that the transformer is correctly wired, the connections between the differential relays and the transformers are correct and that all of the control signals are connected correctly.
2. Setting up the Protection Scheme
Before commissioning the TDPS, it is important to set the protection scheme settings to the intended application. This includes ensuring the relays are set for the correct parameters, such as current settings, time delay settings and trip zones. This must be done carefully as any incorrect settings could result in the system not working properly.
3. Testing the Differential Relays
The next step is to test the differential relays. This is done using a test signal, which simulates an external fault within the transformer. The signal is sent through the relays and the response should be within the expected parameters. If the signal is not reaching the relays, the connections should be verified to identify the issue.
4. Performing a Transformer Differential Test
Once the relays have been tested, a transformer differential test must be conducted. This involves the relay settings being set in accordance with the application and the relays being tested by simulating an internal fault within the transformer. This test should show the relays responding as expected within the desired trip settings.
5. Testing the Trip Circuit
The final step in the TDPS commissioning process is to test the trip circuit. This involves applying a test signal to the trip circuit and verifying that the trip circuit is functioning as designed. If any issues are found, the connections should be checked and any faults corrected.
Conclusion
The commissioning of the TDPS is a complex procedure, which must be undertaken with care. By following the steps outlined in this paper, it is possible to properly commission the TDPS, ensuring that the protection system is correctly configured and functioning as expected. This ensures the transformer is correctly protected from any external or internal faults, which could lead to serious damage or disruption.
