INSULA

Current Transformers

Indoor, cast resin insulated, support-type M.V. current transformers: IGW - IGWR

Current Transformers (C.T.'s) for measuring and protection purposes with rated primary current up to 2500 A are produced and tested by team of highly qualified and experienced engineers who already have more than 18 years of experience in the design, manufacturing, and testing of INSTURMENT TRANSFORMERS. Top priority shall be given to quality and prompt service to enable us to establish good rapport with our valued customers.
All our manufactured transformers are tailor-made since specifications are generally decided by the user (in consultation with manufacturer). It is therefore not possible to furnish dimensional details and price in advance. These details can be given only after going through the enquiry. C.T.'s with customer specification can be manufactured and supplied on request. Offer for these items shall be sent against enquiries only.

Applications

IGW support-type current transformers for indoor use are employed for measurement and protection purposes in busbar systems of 24 kV medium voltage switchgear with rated primary currents up to 2500 A. These transformers are used to separate metering and protection circuits from high voltage, and to transform the measured current to the values required by the metering and protection devices.
Transformers design
R&D

The continuous research and development at INSULA resulted in the successful new IGWR series. The IGWR series supports the nominal specific creepage distance of 20 mm/Kv for usage in areas with medium pollution level. In this new development the minimum possible dimensions that comply with the requirements of all switchboard manufacturers were considered.
Safety by design

The support-type current transformers of the IGW series are encapsulated in cast-resin housing and potted with polyurethane inside the housing, l.e. the primary winding and the secondary core-and-coil assembly are embedded in a single operation, thus guaranteeing optimum insulation resistance. The secondary core-and-coil assembly consists of a maximum of three soft magnetic, highly permeable tape-wound toroidal cores, each core being uniformly wound. The output terminals consist of an M5 terminal pair. One screw of each terminal can be used for direct earthing to the base plate.

The output terminals are protected against accidental contact by a sealable transparent cover in self-extinguishing polycarbonate.

During the final inspection the transformers are subjected to a routine test in accordance with the relevant national and international IEC standards.
Installation – no problems, no maintenance

The principal dimensions of the IGW models satisfy DIN 42600 Part 8. Each model requires no maintenance and can be mounted in any position.

Description of main parts
Cores used in C.T. are made either of high quality thermally treated cold rolled grain oriented steel sheet (g.o.s.s.) or some soft magnetic material (mumetal), depending on the accuracy class required.
Windings
Secondary winding, designed as multilayer winding, is wound on the core with additional insulating layers. Primary winding is designed in such a way that mechanical stresses due to thermal dilation, in case of short circuit currents, are not transmitted to the main insulation of the transformer.
Terminals
Primary terminals are made of brass or copper and equipped with M12 tightening screws. On the transformers with primary change over, the transformation ratio is changed by simple arrangements of links. Secondary terminals are made of brass and closed with appropriate cover tightened to the transformer body.

*Caution*
If C.T. operated open circuited on the secondary side, extremely high voltage can be generated with resultant damage to equipment and personnel.

Current Transformers (C.T.s): SPECs
INSULA produces and supplies a wide range of C.T. products with various combinations chosen from the different technical parameter range, complying with customer specifications according to IEC 60044-1(2003).

Standard specification to which INSULA current transformer comply:

Rated primary current	25 …. 2500 A (intervals of 5)
Rated secondary current	5 or 1 A
Accuracy class: 'M' Wdg 'P' Wdg.	Class X (available on request) 0.2 , 0.5 or 1 Fs < 5 or10 5 or 10P 10/15/20
Rated Output	5…….up to 60 VA
Highest system voltage (kV)	3.6 7.2 12 17.5 24
Rated insulation level (kV)
Power frequency - 1 min. test Impulse	10 20 28 38 50 40 60 75 95 125
Rated short time
Thermal current Ith. Dynamic current Idyn.	Min. 100 x In KA 2.5 x Ith (max. 100 kA.)
Rated continuous thermal current	120……….150% In A
Rated frequency	50 – 60 Hz.
Insulation class	E
Number of secondary cores	up to…. 3
Multi Ratio CT with Change over on Primary side	Up to …600-1200 A

Guarantee Table

Medium Voltage Current Transformer 12KV

Standard and relevant publication	IEC 60044-1(2003)
Name & place of manufacturer	INSULA –Egypt
Winding material (Primary / Secondary)	Copper
Winding / filling/ envelope insulation material	Cast Resin
Insulation level	12/28/75 kV
Rated frequency	50/60 Hz.
Insulation class	E (max. temp. rise 75 Co)
Ambient temp. Co	-5 to +40
Rated contentious thermal current (A)	1.2 x In.
Rated short time thermal current Ith. (kA)	Specified by customer
Rated dynamic current Idyn. (kA):	2.5 x Ith (100 kA max.)
Rated primary	25..…2500 (intervals of 5) A.
Rated secondary current	5 or 1 A.
Partial discharge (PC)	According to IEC
One minute Power Frequency Test	28 kV
Power Frequency Test voltage between	Sec. Insulation: 3 kV. Interturn: 4.5 kV. (peak)
Ratio error % & phase displacement	According to IEC
Security factor "FS"	5 or 10
Rated Secondary burden	2.5….….60 VA
Accuracy Class	Measuring Winding 0.2/0.5/1 Protection Winding 5 or 10 P 10/15/20

Medium Voltage Current Transformer 24KV

Standard and relevant publication	IEC 60044-1(2003)
Name & place of manufacturer	INSULA –Egypt
Winding material (Primary / Secondary)	Copper
Winding / filling/ envelope insulation material	Cast Resin
Insulation level	24/50/125 kV
Rated frequency	50/60 Hz.
Insulation class	E (max. temp. rise 75c)
Ambient temp. Co	-5 to +40
Rated contentious thermal current (A)	1.2 x In.
Rated short time thermal current Ith. (kA)	Specified by customer
Rated dynamic current Idyn. (kA):	2.5 x Ith (100 kA max.)
Rated primary	25..…2500 (intervals of 5) A.
Rated secondary current	5 or 1 A.
Partial discharge (PC)	According to IEC
One minute Power Frequency Test	50 kV
Power Frequency Test voltage between	Sec. Insulation: 3 kV. Interturn: 4.5 kV. (peak)
Ratio error %&phase displacement	According to IEC
Security factor "FS"	5 or 10
Rated Secondary burden	2.5….….60 VA
Accuracy Class	Measuring Winding 0.2/0.5/1 Protection Winding 5 or 10 P 10/15/20

Testing

Our testing laboratory is well equipped with all facilities to conduct routine tests on our products. Complete testing facilities are available in-house with calibrated equipment periodically. These tests shall be conducted in accordance with relevant national and international standard specifications IEC 60044-1(2003). We also provide tailored tests according to customer specifications and requirements. In addition to the Routine Tests that are performed for each product, all our products are Type tested as well.

Testing phases:
We have a three-phase test for all our products.
- Winding Accuracy Check:
This is the first test that is done to ensure the proper installation of the cores and winds when the current passes.
- Pre-cast Testing:
This test is done to ensure the right functioning of the primary and secondary windings before the casting material is filled up.
- Final Testing:
This is done for the whole product before delivery. Each product should pass this test and a final testing report is placed and packed with it.
Our team of engineers ensures quality of raw materials, materials in process, and finished products. Complete tests reports shall be made available for each transformer manufactured.
Distribution & Delivery Period:

INSULAs’ products are not distributed through distribution channels due to thenature of the product and the variety of the specifications. Offers and orders of our products are placedthrough direct contactwith the factory and the head office. Orders are then processed and delivered from the company directly to our clients. Expected delivery period shall be 4 to 8 weeks from order time depending up on items and quantity required. We can also provide flash delivery within one week according to materials available and order size.
Packaging:
Each product is separately packed with a data sheet enclosed containing all the specifications and testing results. In addition, stickers of all information are provided on the products to facilitate usage. The packaging material is hard made to ensure the product is not damaged during transportation and/or delivery.