Efficient current transformer testing with omicron ct analyzer. If both ds are closed and current will go to both relays. Transportation, erection, testing and commissioning ieema. Evidence shall show that knowledge has been acquired of designing testing and commissioning procedures for substation and field devices. As an industry, we have replaced detailed drawings with electronic settings files. To add a password to your powersuite software navigate to settings then preferences and under the security section select your user id, you can then adjust your user level and add a password. Commissioning process for new substation equipmenthayes. 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. As part of this project, startup services will be performed on the electrical distribution and control equipment as specified. Repeat the test for the other phases and the other secondary cores.
Technical specification for startup and commissioning of new. The focus of the exam is on source inspection issues and activities rather than design or engineering knowledge contained in the reference standards. This happens because the main function of protection devices is related to operation under fault conditions so these devices cannot be tested under normal operating conditions. Injection testing to confirm ct quality and suitability is carried out as part of the testing regimes for these items, no ct injection tests should, therefore, be required. Insulation resistance and continuity of the winding should be checked by v megger 3. When current flow exceeds that rating, the metering core will become saturated, thereby limiting the amount of current level within the device. It is expressed in per unit or percent of the rated transformer winding. Transformers while experiencing severity of short circuit current looses its mechanical property by way. 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. Application manual technical reference manual installation and commissioning manual operator. Strategy and other partial discharge documents or consult. Pdf the effect of inrush current on transformer protection. Resistance r voltage e current i at that time, the standards for voltage, current and resistance had not been developed. Each electrical method statement folder contains editable files like.
Instrument transformer testing instrument transformers for metering purposes must have a high degree of accuracy up to class 0. Testing these features confirm that the relay properly. The half wave rectified signal looks partially like the current generated at the start of a transformer magnetising inrush event. Icf assessment of large power transformer risk mitigation strategies 4 1. Commissioning procedure of power transformer in transformer testing it can be classified into power and distribution transformers. Commissioning of distribution transformer before actually charging the transformer the following points should be checked. The commissioning and maintenance personnel must be well experienced in using protection equipment, test equipment, protection. Operation, maintenance, and field test procedures for protective relays and associated circuits iii acronyms and abbreviations a ampere ac alternating current amp ampere ansi american national standards institute bes bulk electric system carma capital asset and resource management application ccvt coupling capacitor voltage transformers co. The transformer testing performed before commissioning the transformer at the site is called the precommissioning test of transformer. Protection relay testing and commissioning the testing and verification of protection devices and arrangements introduces a number of issues. The parts mentioned on the drawing are to be checked for physical mounting.
Purpose and scope of the study the office of energy policy and systems analysis epsa, in consultation with the office of electricity delivery and energy reliability oe, of the u. The usual procedure is for the person operating the battery connections to. 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. Testing current transformers burden test only if we cannot get to the primary side of the ct we can. Technical specification for startup and commissioning of new products specification number. The external connections to the terminals of ret 521 shall be made in accordance with the valid terminal diagram. Transformer bushing cts should be tested using the current ratio test method. To confirm the physical condition and electrical characteristics of current transformer installed in the installation. Transformer erection testing commissioning power transformer erection electrical engineering welcome to the. All oil valves are in correct position closed or opened as required. Circuits must be isolated from one another, and surge protection devices removed.
Ks01tts24a testing and commissioning procedures for field devices and substations design. Can you provide me with a test format or a sample of test report please. Sp0504 power transformer testing swp pdf file, 110. Before proceeding with commissioning it is important to check that. Dec 09, 20 the ct secondary current will select the relay by ds contacts status. He has vast experience in the design and development of transformers. Power transformer testing transformers may be tested using ac or dc voltage. Mainly two types of transformer are done by manufacturer before dispatching the transformer mainly 1 type test of transformer and 2 routine test. All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies.
For a technician, the diagram did more than explain the circuit,it provided a troubleshooting and testing road map. Electrical shock electrical shock and its effects can be caused and influenced by several factors. The commissioning personnel must have a basic knowledge of handling electronic equipment. Short ct links then isolate the external wiring to confirm ct circuit will not be opened. 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. In addition some other tests are also carried out by the consumer at site before commissioning and also periodically.
All transformers are subjected to the following pre commissioning. The first author worked in the transformer industry for 11 years before joining academia. The time specified would depend on the protection in the circuit. Assessment of large power transformer risk mitigation strategies.
Download electrical method statements method statement hq. Feb 08, 2015 the test performed before commissioning the transformer at site is called pre commissioning test of transformer. Connection on cpc100 will be same as the shown figure. Uettdrts24a design testing and commissioning procedures. Introduction the importance of a well thought out and executed commissioning process cannot be overstated given the current environment in which electric utilities operate. Current transformer manual manufacturers drawings 4. Current transformer white paper the basics of current transformers ratio the ct ratio is the ratio of primary current input to secondary current output at full load. 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. Kindle file format testing and commissioning of electrical. Scribd is the worlds largest social reading and publishing site.
Replaces 7200pd9206, 031992 medium voltage transformer. Ct analyzer the number one in current transformer testing. Frequently asked powersuite software questions megger. This protects connected metering devices from overloading in the presence of fault level current flows. We notice a recurrent underestimating in all transformer tests despite the huge influence. Additional checks during commissioning of power transformer.
Ct analyzer current transformer testing, calibration and. Commission testing methods for protection systems mipsycon. Current transformers testing and commissioning guidelines. Commissioning engineers often work under difficult time constraints. Testing and commissioning of current transformer free download as pdf file. Credentials, background and education, company focus, client. Timesaving test automation for standard test procedures is also a must for meeting the deadlines of a time sensitive environment. Lessons learned from commissioning protective relaying. Department of energy doe directed this study to begin.
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. This manual addresses the personnel responsible for commissioning, maintenance and taking the ied in and out of normal service. Instrument transformer theory and testing steve hudson, pe. Commission testing data is baseline for the lifecycle maintenance date of commissioning records define time 0 for prc005 current and voltage measuring device insulation failure detected battery and charger performance degradation observed communication channel degradation flagged. Noload loss tests are measured at 100% of rated voltage. It buffers the meter from experiencing excessive torques that might be. Testing and protection of current transformer practical experiences. Transformer is the most important equipment in the electrical power transmission and distribution system.
When 1a ds closed and current will go to 1a relay through early make and late break 1a ds contact. If 1b ds closed current will go to 1b relay through early make and late break 1b ds contact. There are various test required on transformer to conform performance of transformer. Transformer should be inspected by authorized electrical inspector and get permission to energize the same 2. Operation, maintenance, and field test procedures for protective relays and associated circuits iii acronyms and abbreviations a ampere ac alternating current amp ampere ansi american national standards institute bes bulk electric system carma capital asset and resource management application ccvt coupling capacitor voltage transformers co 2. Current transformer testing swp check this is the latest process zone version before use. Commissioning process and acceptance test of a sub harmonic. The availability of equipment is essential for adhering to these time schedules. These tests are done to assess the condition of transformer after installation and compare the test results of. Primary injection testing, as opposed to the secondary injection test, is the only way to prove correct installation and operation of the whole protection chain, as the test involves the entire circuit.
The chapter safety information presents warning and note signs, which the user should pay attention to. The purchase, preparation, assembly, operation and maintenance of transformers represent a large expense to. Testing also is available through the plants extra high voltage laboratory ehvl. Operation, maintenance, and field test procedures for. The basics of current transformers nk technologies. Pre commissioning of power transformer engineering essay. Power transformer testing and commissioning guidelinesoil. The mrct automatically calculates ratio errors, saturation curves, and knee points. Individual product startup procedures must be submitted and on file with startup service company office 10 days. Figure 2 showed the flow chart when doing the testing on precommissioning of power transformer.
Ohms law expressed the fact that the magnitude of the current flowing in a circuit depended directly on the electrical forces or pressure and inversely on a property of the circuit known as the resistance. Check the following points before start the transformer testing and commissioning. The megger mrct is a light weight, robust, portable unit used to perform demagnetization, ratio, saturation, winding resistance, polarity, phase deviation, and insulation tests on current transformers. 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. Uettdrts24a design testing and commissioning procedures for. In the past, detailed control schematics served as a visual description of our intended scheme. Secondary current injection the current transformer which is used for ldc purposes will be mounted either at the transformer or the transformer lv circuit breaker. Testing and commissioning of current transformer scribd.
Reference 40 reported that inrush current can damage the variable speed drive in hvac and refrigeration systems while, reference 41 addressed the effect of inrush current on the transformer. It focuses only on the tests and equipment needed to minimize electrical shock and does not discuss mechanicalphysical injury and fire hazards. Lessons learned from commissioning protective relaying systems. Unfortunately the megger powersuite software is not compatible with apple mac products. This test determines the current required to maintain the magnetic excitation of the core. Some most recent works are also discussed to give readers a feel for the latest trends in transformer technology. Testing power transformers highvoltage transformers are some of the most important and expensive pieces of equipment required for operating a power system. For all ct loops, each loop must have only one earth point, otherwise secondary current will be divided. Replaces 7200pd9206, 031992 medium voltage transformer testing. Check for level, colour of oil in the sight glass for outdoor current transformers. Assessment of large power transformer risk mitigation. Power transformer testing and commissioning guidelines r. Protective relay and protection system commissioning.
Precommissioning tests and functionality assessment of a bulk. Contents chapter page chapter 1 introduction 1 introduction to the installation and commissioning manual 2. Feb 07, 2018 testing and commissioning of electrical equipments. The following tests are routinely conducted in the field on the transformer. The toshiba transformer plant in contagem, brazil is a leading exporter of oits to north america. This page gives full list of electrical method statements which you can download as per your requirements. Guide for source inspection and quality surveillance of. Testing and commissioning instrumenttransformers free download as powerpoint presentation. The stateoftheart facility of more than 380,000 square feet routinely produces oits up to 550 kv and 700 mva. Protective relay and protection system commissioning omicron. Hence, it is essential to inspect and calibrate those instrument transformers at regular intervals.
1349 473 671 228 981 868 706 1503 1325 173 602 609 122 1029 1269 328 215 1002 542 915 687 1212 1221 105 1411 709 876 1575 478 214 148 274 208 622 1136 822 969 1016 4