Let’s know learn more about the 500kVA transformer
This article is about the 500 kVA distribution transformer brief introduction and description.
It is introduced from different angles of his basic tech spec, including voltage range, BIL (Basic impulse level) level and temperature rise level,its structure, including HV bushings and LV bushings, oil, etc.,as well as its accessories requirements of the 500 kva distribution transformer.
Daelim is a manufacturer that can produce single-phase, three-phase transformers. Voltage level to 220kV, capacity to 100mva.
Has CSA/UL certificate. Daelim transformers have good performance, long service life and short production cycle, which can meet your delivery requirements.
Oil immersed transformer
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Basic tech spec of the 500 kva distribution transformer
Especially when you need to buy a 500 kVA distribution transformer, you must know some basic technical specifications.
It is convenient for you to buy the right and correct transformer.Then let’s take a look at the basic technical specifications of the transformer!
Transformer high and low voltage
We already know that the transformer capacity is 500kva, so we must also know how much the input high voltage and output low voltage are.
If it is between procurement, it only needs to comply with local standards; but if it is a transformer bidding project, it must be designed in strict accordance with the specific requirements of the bidding documents.
There are also differences in different regional standards, such as Canada, which adds some CSA standard requirements on the basis of American Standard.
Therefore, when looking for transformer suppliers, it is particularly critical and important to know whether they understand these standard requirements and whether they have experience in producing such standard transformers.
About the temperature rise of the 500kva transformer shall be 65º C. Revise to 55 deg if a more robust transformer is required.
Voltage regulation range
The voltage tap of the 500 kva distribution transformer,generally provide a no load tap changer with 2 ± 2 ½% FCAN (full capacity above normal) & FCBN (full capacity below normal) located in the primary windings for the transformer.
The tap changer shall have an externally operated handle, position indicator with provision for padlocking. The tap position shall be clearly marked on the tap changer dial plate.
A warning notice shall be applied adjacent to the handle of the tap changer stating: “WARNING OFF CIRCUIT TAP SWITCH – OPERATE ONLY WHEN TRANSFORMER IS DE-ENERGIZED .”
If it is a three-phase 500kva oil transformer, three high-voltage bushings and three low-voltage terminals should be installed.
High pressure bushings are designed in a minimum 4 hole pattern designed for long barrel compression lugs. Low pressure bushings are designed with at least 8 holes in a pattern designed to accommodate long barrel compression lugs.
All bushings of the transformer shall be designed to match the installation identified on the drawing.
Provides flexible bus connectors rated for the highest bus ampacity for bus connected high or low voltage bushings.
Transformer accessories brand requirements
The accessory brand has many effects on the transformer cost.
The price of international famous brand accessories is many times higher than that of ordinary brands. You can choose the accessory brand according to your transformer budget.
Core construction of the 500 kva distribution transformer
For delta-wye transformers the coils shall be circular wound with adequate bracing and blocking to minimize the effects of short circuit. Use of adhesive as a primary means for strength is not acceptable. Strong “keep back” insulation is required on the outer layers of the HV windings along with proper mechanical bracing between winding sections.
If the windings of the transformer are a Y-Y configuration, the transformer core to be a five leg type.The conductor of the 500 kva distribution transformer, windings and bus material shall be copper unless otherwise noted. The copper or aluminium used shall have a 99.9% high conductivity.
Copper windings shall be designed using a maximum current density of 1800 Amps/square inch and aluminum windings shall be designed using a maximum current density of 1200 Amps/square inch.
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Transformer construciton of the 500 kva distribution transformer
The 500 kva distribution transformer shall be of a sealed tank structure, the thickness of the welded steel plate is suitable to withstand without permanent deformation, and the positive and negative pressures are 25% larger than those specified on the nameplate.
Tank wall stiffeners should be made of formed steel to maximize strength to ensure field filling.
The outer surface of the 500 kva distribution transformer should be sandblasted or sandblasted clean, and all oil and foreign matter should be removed before painting. The exterior should be coated with one coat of anti-rust primer followed by two top coats for a minimum total dry film thickness of 3 mils. The inside of the tank should be cleaned to remove all metal scale and foreign matter. The interior should be painted with anti-paint in areas 4 inches below normal oil level.
All welding shall be in accordance with CSA W47.1, CSA W57 or other required standards. Lifting moving and jacking facilities capable of handling the total fill mass should be provided.
Anchorages are provided to set the formwork for securing the transformer. At least four (4) heavy duty lifting lugs with holes suitable for securing lugs for transporting transformers. The lugs must be sized to be strong and not deform during use.
The transformer shall have a structural steel I-beam base.
Manholes or handholes of suitable size and location should be provided. For tamper-proof transformers, there should be a shroud over the access hole c/w for pad locking.
The cover is bolted to the tank. For tamper-proof transformers, the cover should be welded to the tank.
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500 kva transformer in tamper-resistant construction
For tamper proof construction of the 500 kva distribution transformer, usually it is pad mounted transformer.The following is to be provided:
1 All of the protect gauges and the oil valves, primary bushings and secondary terminals, tap changers, pressure relief device for oil. should be contained with transformer’s tank.
2 All of the enclosures should be stainless steel, and the color can be gray as the standard. or as customer’s requirement for specific project.
3 If the capacity larger than 1500kva, 2000kva, or 2500kva, The bottom of the tank of thhe transformer should have the wheels, to move it convenient.
4 Access to the compartment shall be provided by a door hinged with a minimum of 5 pin type hinges and shall have three (3) Pentahead bolts with at least one having provision for padlocking. The door shall be constructed of a minimum of 11 gauge steel. Normal entry shall be possible only with the use of proper access tools.
5 All of the transfomrers need to put the danger tips as standard, in case have the dangerous.
6 All of the doors should have no bolts or nuts be exposed, and at least have three pentahead bolts in the bottom of the transformers as detailed in the standard CAN/CSA C227.4
7 Pentahead bolts must be corrosion resistant and their design shall minimize the possibility of misalignment and cross threading. The pentahead bolt shall be supplied with a non-rotating guard such that removal of the bolt is possible only by the proper tools.
8 Equipment shall have no external means of operation of switching equipment nor shall it have an external glass viewing window.
9 There shall be no exposed screws, bolts, or other fastening devices that are externally removable, except for any auxiliary fastening device that may be specified by the purchaser.
10 There shall be no openings through which foreign objects such as sticks, rods, or wire may be inserted to contact live parts.
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Accessories requirement of the 500 kva distribution transformer
All accessories of the 500 kva distribution transformer are to be wired and terminated in a NEMA 4 weatherproof control cabinet enclosure with hinged front door with provision for padlocking and it shall include a bolted bottom entry plate for customer cables or conduits and shall have dimensions of not less than 406 mm x 406 mm x 150 mm to allow for ease of access and shall be bolted to the transformer to allow for interchangeability. All conduits to be flexible liquid tight conduits.
Provide termination board in the enclosure and label all terminations appropriately. All devices are to be wired back to enclosure with wiring type as per manufacturer’s recommendations.
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500 kva distribution transformer testing
All standard factory testing are to be witnessed by the Technical Service Start-Up,Services Contractor, the Owner and the Engineer’s Representative.
The transformer shall be tested in accordance with the provisions of ANSI C57.12.90. All the tests listed herein are to be done in the order that they are listed. All tests are to be completed on all transformers.
As a minimum perform the following tests:
1 Resistance Measurements of the 500 kva distribution transformer
2 Turns ratio test is performed between windings for all tap positions.
3 Polarity and phase rotation of the 500 kva distribution transformer
4 Excitation Current and no load losses on rated voltage and 110% of rated voltage.
5 Impedance and load loss of the 500 kva distribution transformer
6 Applied potential of the 500 kva distribution transformer
7 Induced potential of the 500 kva distribution transformer
8 Pressure test of the 500 kva distribution transformer
9 Core insulation test of the 500 kva distribution transformer
10 Insulation power factor test of the 500 kva distribution transformer
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Customized 500kVA transformer
Daelim is a Chinese transformer supplier specialized in the international market. The technical team has rich experience in international standard transformer design, such as IEC, IEEE, ANSI, AS, CSA, DOE, GOST, etc. Therefore, no matter what country and region you are from and need any standard of 500kva transformer, Daelim can design and produce it.
Will The 300kva transformer Testing According to CSA or IEEE standard?
Daelim Transformer’s answer is “Yes!”
A type test is a test made by the manufacturer to verify a design characteristic not covered by a routine test.
Upon request, the manufacturer shall provide a record of type tests to the purchaser at the time of order. The test data may be provided from tests performed on other units whose equivalence, with regard to each required test, is acceptable to the purchaser.
9.1 Standard type tests
The following are the standard type tests:
(b) temperature rise;
(c) impulse strength;
(d) radio-influence voltage;
(f) transformer integrity; and
(g) audible sound.
9.2 Dielectric tests
The transformer and cable entrance compartment assembly shall be of a type that has been tested to
demonstrate that it successfully withstands overvoltage tests equivalent to those required in CSA Clause 7.2 when equipped with such high-voltage accessories as may be provided by the manufacturer.
9.2.2 Applied voltage test
The applied voltage test shall be performed by applying, between each winding successively and the other winding(s) connected to ground, a voltage at 60 Hz from an external source, of the kV value specified. Such applied voltage shall be held constant for 1 min. This test shall not be performed on any winding that is permanently grounded.
9.2.3 Induced voltage test
126.96.36.199 Transformers with delta-connected high-voltage windings
For transformers with delta-connected high-voltage windings, the induced voltage test shall be performed by applying between the terminals of one winding, with the other winding open-circuited, a voltage of twice the normal voltage of the winding for 7200 cycles at one of the frequencies specified in CSA Standard.
188.8.131.52 Transformers with permanently grounded Y high-voltage windings For transformers that have a Y-connected high-voltage winding with the neutral terminal permanently grounded, the induced voltage test shall be performed by applying to the line terminals of one winding a voltage that will develop between the high-voltage line terminals a voltage equal to the values given under applied voltage in CSA Standard for 7200 cycles at one of the frequencies specified in CSA Standard.
However, in no case shall this voltage between the high-voltage line terminals be less than twice the rated transformer line voltage or more than 1000 V plus 3.46 times the rated transformer line voltage.
9.2.4 Impulse tests
The standard impulse tests shall consist of voltage applied to each winding, in accordance with CSA Standard, in the following order: one reduced full wave followed by one full wave.
9.2.5 Temperature rise test
9.2.6 Short-circuit tests
9.2.7 Transformer integrity test
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What Kind Of Support If The 300KVA Transformer Has Any problem?
Daelim Transformer has exported electrical equipment over 16 years, entered North America market 4 years ago.
Because of the high quality with good performance, has the good reputation in North America.
Daelim has built their own after-sales center, our after sales team will support you for any problem
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How About The Warranty Time The 300KVA Transformer Manufacturer Will Give?
Daelim Transformer give customers 2 years warranty time, under normal use environment and temperature, the service life can be as long as 30 years or even longer.If you have any questions about the 300kva transformer, you can always contact the Daelim team to help you.