Testing and commissioning of electrical equipments vtu notes pdf. As you already know, substations are the points for controlling the supply of power on different routes by means of various equipment such as power transformers, circuit breakers, ctsvts, compensating equipment, isolators, etc. Ac voltage is preferable to dc voltage for transformer testing because ac voltage simulates the internal stress that the transformers face during operating conditions. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically. Inspection, testing and commissioning of electrical. Transformer bushing cts should be tested using the current ratio test method. Power transformers are subject to several electrical, mechanical, thermal, and environmental stresses during regular operation, with an expected life cycle of more than 30 years. Remove the neutral ground and isolate the ct from any associated burden. The cables from the current and voltage transformers should be identified with regards to phases and connected to the proper terminals. Installation and commissioning manual protectit transformer protection terminal ret 5212. Power transformer testing and commissioning guidelines r. Short ct links then isolate the external wiring to confirm ct circuit will not be opened. Testing and commissioning instrumenttransformers free download as powerpoint presentation.
For all ct loops, each loop must have only one earth point, otherwise secondary current will be divided. Heres a summary of the current transformer testing paper. Additional checks during commissioning of power transformer. Transformer precommissioning tests and afterreceipt. Below we have list all the links as per the modules. These tests are done to assess the condition of transformer after installation and compare the test results of all the low voltage tests with the factory test reports. View and download megger sverker 900 application note online.
Current transformers ct and voltage transformers vt. In order to ensure availability of uninterrupted power supply, it is essential that the condition of transformer is continuously monitored during service as failure of transformer would result in interruption of power supply resulting loss of industrial production and inconvenience to. This manual addresses the personnel responsible for commissioning, maintenance and taking the ied in and out of normal service. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. Transformer testing commissioning, routine, diagnostic. When current flow exceeds that rating, the metering core will become saturated, thereby limiting the amount of current level within the device. Each electrical method statement folder contains editable files like. Check the following points before start the transformer testing and commissioning.
The typical excitation current test data pattern for a threelegged core transformer is two similar current readings and one lower current reading. As part of this project, startup services will be performed on the electrical distribution and control equipment as specified. The dc voltage test momentarily imposes a small dc voltage on one side of a ct primary and the direction of the momentary deflection of a meter on the opposite side secondary. Designed to test current, voltage and combined transformers. If you are interested in full list of method statement for electrical testing and commissioning please. Scribd is the worlds largest social reading and publishing site.
A primary part of commissioning a transformer involves testing it after its installation in the field. It buffers the meter from experiencing excessive torques that might be. Power transformer testing and commissioning guidelinesoil. Download electrical method statements method statement hq. Testing and commissioning of electrical equipments vtu. Before do the testing, the testers must be following the guideline to avoid the most accident because testing work on transformer need to be done carefully and cautiously. Testing current transformers burden test only if we cannot get to the primary side of the ct we can. Commissioning procedure of power transformer in transformer testing it can be classified into power and distribution transformers. Check for cracks in door current transformers, and that equipotential point of window type cts has been connected to the busbar. There are various test required on transformer to conform performance of transformer. It is often found that current transformers with secondary ratings of 1a or less have a. Turnsratio test results should not deviate more than onehalf percent from either the adjacent coils or the calculated ratio. Routine tests and type tests of transformers electrical4u. To confirm the physical condition and electrical characteristics of current transformer installed in the installation.
Services offered in the area of consulting, commissioning, testing, diagnosis and training make the product range complete. Insulation tests on current transformers rated 600v or less are usually performed at vdc. This gl o macs startup, commissioning and testing of electrical systems training seminar has been designed to provide a clear and perfect understanding of principles of commissioning and electrical installation equipment readiness for a commercial service is proven by testing all its functions under different conditions. Testing and commissioning of electrical equipments vtu notes pdf of total units. However, this is not to say that this book is useless to students the easy to read question and testing and commissioning of electrical equipments by s rao format serves as a guiding light to those who wish to attempt higher level competitive exams and need to brush up on the basics because they are otherwise too bogged down with heavy theoretical. Instrument transformer theory and testing steve hudson, pe. Instrument transformer testing instrument transformers for metering purposes must have a high degree of accuracy up to class 0. All materials and relevant documentation to this testing works shall be checked by the responsible personnel prior to the commencement of testing activities.
The usual procedure is for the person operating the battery connections to. Ensure the ct is connected to system properly in all respect primary and secondary. Ct analyzer current transformer testing, calibration and assessment. The commissioning personnel must have a basic knowledge of handling electronic equipment. Switchgear testing and commissioning procedure electrical. This amounts to a rigorous examination of the transformer intended to. Figure 2 showed the flow chart when doing the testing on pre commissioning of power transformer. Current transformer ct testing procedure in sulation resistance measurement. Before commencement of any test make sure the surroundings near clear off from any unwanted materials etc, and make proper approach, scaffolding etc. Current transformers testing and commissioning guidelines. Sp0504 power transformer testing swp pdf file, 110.
Twowinding transformers have terminals designated by h and x e. The magnetizing current can be measured by feeding 400 v, three phase 50 hz supply from hv side keeping the lv side open circuited and the value in different phases could be compared. Feb 07, 2018 testing and commissioning of electrical equipments. Technical specification for startup and commissioning of new. Sverker 900 measuring instruments pdf manual download. After commissioning, secondary current measurement shall be carried out in ct circuits. Testing and commissioning of hv power transformers, circuit.
All transformers are subjected to the following pre commissioning. Sep 28, 2018 current transformer ct testing procedure in sulation resistance measurement. Therefore, transformer under test may be demagnetized before commencement of magnetizing current test. Nov 17, 2019 the magnetizing current can be measured by feeding 400 v, three phase 50 hz supply from hv side keeping the lv side open circuited and the value in different phases could be compared. May 10, 20 the transformer testing performed before commissioning the transformer at the site is called the pre commissioning test of transformer. This protects connected metering devices from overloading in the presence of fault level current flows. This method statement will give a brief steps to be carried out for testing and pre commissioning of transformers. A routine series of diagnostics and testing for your current transformer should include ct saturation testing to identify the knee point against ieee or iec standards, ct ratio tests to identify that the voltage ratio is within expected parameters and current transformer resistance testing for both the transformer windings and ct insulation. Before starting transformer testing some of the percommissioning checks a physical inspection of the transformer is to be carried out along with the general arrangement drawing. Phase angle check shall be done for correct direction.
Ct analyzer the number one in current transformer testing. It rating plate show nominal voltage, current of primary and secondary voltage at various of the tap changer, connection symbols vector group, % impedance weight of oil etc. The following tests are routinely conducted in the field on the transformer. Pdf electrical power system by jb gupta pdf download.
Pre commissioning of power transformer engineering essay. Substation maintenance and commissioning test equipment. These tests are common to perform for instance during commissioning. Terminal marking of power transformers is determined by ansi standards. Transformer is the most important equipment in the electrical power transmission and distribution system. Testing will commence only after the equipment is completely installed as per approved method statement for the installation of the transformer and released for testing commissioning. Verify that current and potential transformer ratios correspond to drawings. For nonconventional instrument transformer ncit testing, lower test signals may. Technical specification for startup and commissioning of. Check for level, colour of oil in the sight glass for outdoor current transformers. The instrument current transformers supply, and isolate, the secondary relays, meters and other instruments, providing the suitable and manageable secondary quantities which are proportional to those in the primary. The commissioning and maintenance personnel must be well experienced in using protection equipment, test equipment, protection. Electrical power system by jb gupta is very useful for basics ideas of power system and best for competitive exams and topics are covered in sufficient details. H 1, h 2, x 1, x 2, where h is the higher voltagerated winding and x is the lower voltage winding.
The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of transformer. All oil valves are in correct position closed or opened as required. Efficient current transformer testing with omicron ct analyzer. Power transformer iec 60670 power transformer power transformer testing and commissioning pdf modern power transformer practice pdf modern power transformer practice paperback design operation maintenance of core type oil filled power transformer transformer transformer applications transformer protection pdf mind transformer transformer. Power transformer iec 60670 power transformer power transformer testing and commissioning pdf modern power transformer practice pdf modern power transformer practice paperback design operation maintenance of core type oil filled power transformer transformer transformer applications transformer protection pdf mind transformer. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals.
Do not believe, until it is proven is the key to successful. Apr 03, 2017 before starting transformer testing some of the per commissioning checks a physical inspection of the transformer is to be carried out along with the general arrangement drawing. Back to the basics current transformer testing ct as test equipment becomes more sophisticated with better features and accuracy, we risk turning our field personnel into test set operators instead of skilled field service technicians. Ct analyzer current transformer testing, calibration and. Here you can download the testing and commissioning of electrical equipments vtu notes pdf syllabus. This page gives full list of electrical method statements which you can download as per your requirements. Feb 08, 2015 the test performed before commissioning the transformer at site is called pre commissioning test of transformer. Testing and commissioning of hv power transformers.
Figure 2 showed the flow chart when doing the testing on precommissioning of power transformer. Prior to testing, short the primary winding of the ct under test by connecting h1 and h2, then short the secondary winding of the ct under test by connecting x1 and x2x5. Current transformer testing with sverker900 this application note gives examples on how to perform some typical tests on current transformers cts with sverker 900. Power transformer testing transformers may be tested using ac or dc voltage. Book name a course in power systems by jb gupta author j b gupta. The parts mentioned on the drawing are to be checked for physical mounting. Fully automatic current and voltage transformer test set.