CHAPTER 9 COMMISSIONING TEST Introduction Equipment test Subsystem

CHAPTER 9 COMMISSIONING TEST Ø Introduction Ø Equipment test Ø Sub-system Test Ø Test on Protection system Ø Test on Transformer 1

Introduction Commissioning activity follows erection and involves final checks, subsystem test, protection system tests and load tests. The commissioning organizations includes: v v v Commissioning Incharge Control room engineers Test Engineers for AC yard Test engineers for auxiliaries etc Supervisors and electricians mechanics etc for quick repairs v Documentation and field quality engineer 2

Introduction Commissioning Tests are divided in the categories: ◦ Equipment functional checks and test ◦ Sub-system checks and test ◦ Complete system test at low voltage (without voltage) ◦ Performance tests 3

Equipment test The equipment test on each individual equipment are performed in accordance with the site testing plan with all the associated equipment, auxiliaries and subsystem. The purpose of site tests to confirm: ◦ proper site assembly ◦ no transit damage and proper functioning ◦ all main and auxiliary connections have been correctly made ◦ system operate reliably 4

Equipment test The ◦ ◦ ◦ equipment tests include: - Insulation resistance measurement Resistance measurement Phase sequence tests Polarity test Ratio test Operating timing tests Continuity test Mechanical operation tests Sequential operation test Applied voltage test Primary and secondary injection test Functional operation test 5

Sub-system Test The Sub-system Test include: - ◦ Tests on main and auxiliary circuits ◦ Test on protective and control circuits ◦ Test from local points and control room ◦ Current injection test ◦ Applied voltage test ◦ Insulation resistance tests ◦ Functional test 6

Test on Protection system The Test on Protection system include: ◦ Test before energizing the secondary equipment ◦ Test before energizing primary equipment ◦ Synchronizing test ◦ Test on each protective zone ◦ Staging fault tests by artificial fault in protective zone ◦ Tests of injecting current through the secondary circuits 7

Test on Transformer The Test on Transformer includes: - ◦ Core ground test ◦ Transformer Turn Ratio (TTR) test ◦ Doble Test ◦ Megger Test 8

Test on Transformer Core ground test ◦ determines the presence of unintentional ground on the transformer core by checking the core ground resistance using a 1000 V Megger with the core ground disconnected. The TTR test ◦ measures the turn ratio of the windings and detects open circuited and short circuited turns. 9

Test on Transformer The double test ◦ is performed on transformer windings and bushings. Megger Test ◦ is a measure of the Equipment insulation resistance (M Ohm). 10

Test on Transformer Primary Injection Test ◦ These tests are conducted by injecting current through primary circuit of CT Secondary Injection Test ◦ These tests consist of injecting current through the secondary circuits. Phasing Tests ◦ Before paralleling a transformer the following shall be checked: The phase sequence, the polarity the ratio 11