Directorate of Electrical Engineering Naval Headquarters STATEMENT OF TECHNICAL REQUIREMENTS 380V/415V/440V 50HZ/60HZ 3 PH PRIMARY AND 230V 50HZ/60HZ 3PH 4 WIRE SECONDARY CENTRE TAPPED NEUTRAL EARTHED TRANSFORMER EED 50 16 Rev Date Details Prepared by Checked by Approved by 0 Nov 06 CDR Ram Chander JDEE Capt. Sanjeev Kale DEE CMDE V. Karunanithi PDEE NOV 2006 i
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380V/415V/440V 50HZ/60HZ 3 PH PRIMARY AND 230V 50HZ/60HZ 3PH 4 WIRE SECONDARY CENTRE TAPPED NEUTRAL EARTHED TRANSFORMER EED 50 16 1. SCOPE. This statement of requirement covers the manufacturing, testing and onboard commissioning of the power transformers for portable / domestic electrical equipment for use onboard ships. The transformers should be designed to meet the characteristics of input supply voltage for the appropriate load and duty cycle. The design is to cater for the most adverse environmental and electrical conditions. 2. Quantity. The number of transformers required on each ship will differ from ship to ship and the exact requirement will be specified in the Tender Specifications. 3. Input Power Supply. The transformers should be designed to meet the characteristics of the following input voltage for the rated load and duty cycle: 3.1 440V, 60Hz, 3Ph S No Characteristic Description Value (a) Voltage Nominal Voltage 440V Load range Tolerance Average Average Line to Line value of 3 Ph system Line to line voltage of singlephase of 3 phase system Max. Unbalance Max. Modulation ± 5% ± 6% 2% 2% Transients (Excluding Spikes) (Average line to line value for 3 phase system) 1
a. Frequent Transients b. Infrequent Transients (b) Waveform Max. Individual Harmonic Max. total Harmonic content (c) Frequency Nominal Frequency Load range Tolerance Constant Load Tolerance Modulation Infrequent Transients +6% 0.5 Sec 10% 0.5 Sec ± 10% 1 Sec 16% 1 Sec 3% 5% 60 Hz ± 2.5% ± 0.5% 0.25% + 3.75% 2 Seconds 3.75% 2 Seconds 3.2 415V, 50Hz, 3Ph S No Characteristic Description Value (a) Voltage Nominal Voltage Load range Tolerance Average 415V Average Line to Line value of 3 Ph system ± 6% Line to line voltage of single 2
phase of 3 phase system Max. Unbalance Max. Modulation Transients (Excluding Spikes) (Average line to line value for 3 phase system) a. Frequent Transients b. Infrequent Transients (b) Waveform Max. Individual Harmonic Max. total Harmonic content (c) Frequency Nominal Frequency Load range Tolerance Constant Load Tolerance Modulation Infrequent Transients ± 6% 2% 2% +6% 0.5 Sec 10% 0.5 Sec + 10% 1 Sec 16% 1 Sec 3% 5% 50Hz ± 2.5% ± 0.5% 0.25% + 3.75% 2 Seconds 3.75% 2 Seconds 3.3 380V, 50Hz, 3 Ph 3
S No Characteristic Description Value (a) Voltage Nominal Voltage 380V Load range Tolerance Average Average Line to Line value of 3 Ph system Line to line voltage of singlephase of 3 phase system Max. Unbalance Max. Modulation ± 5% ± 6% 2% 2% Transients (Excluding Spikes) (Average line to line value for 3 phase system) a. Frequent Transients b. Infrequent Transients (b) Waveform Max. Individual Harmonic Max. total Harmonic content (c) Frequency Nominal Frequency Load range Tolerance Constant Load Tolerance Modulation +6% 0.5 Sec 10% 0.5 Sec + 10% 1 Sec 16% 1 Sec 3% 5% 50Hz ± 2.5% ± 0.5% ±0.25% Infrequent Transients 4
+ 3.75% 2 Seconds 3.75% 2 Seconds 4. Output Power Supply. The Output Voltage of the Transformers at consumer Terminal shall meet the following specifications: S No Characteristic Description Value (a) Voltage Nominal Voltage 230V Load range Tolerance Average Average Line to Line value of 3 Ph system Line to line voltage of singlephase of 3 phase system Max. Unbalance Max. Modulation ± 5% ± 6% 2% 2% Transients (Excluding Spikes) (Average line to line value for 3 phase system) a. Frequent Transients b. Infrequent Transients +6% 0.5 Sec 10% 0.5 Sec +10% 1 Sec 16% 5
1 Sec (b) Waveform Max. Individual Harmonic 3% Max. total Harmonic content (c) Frequency Nominal Frequency Load range Tolerance Constant Load Tolerance Modulation 5% 50Hz/60Hz ± 2.5% ± 0.5% 0.25% Infrequent Transients + 3.75% 2 Seconds 3.75% 2 Seconds 5. Scope of supply. The following ratings of transformers will comprise the scope of supply for one ship: 5.1 2.5 KVA Δ/ Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral output. 5.2 5 KVA Δ/ Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral output. 5.3 10 KVA Δ/ Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral output. 5.4 20KVA Δ/ Υ 230V, 3 Ph, Secondary centre tapped for two leads neutral output. 6. Design Requirements. 6.1 Winding. The windings of the transformers should be double wound, dry type and naturally air cooled. The transformer shall conform to specification NES 539 (section 6), NES 535, NES 537 and other naval specifications as applicable. The winding should be so carried out to meet the following requirements: 6.1.1 Primary Voltage: 380V/415V/440V, 50Hz/60Hz, 3 Ph. 6.1.2 Rating: 5KVA to 20 KVA 6
6.1.3 Primary Winding: Delta connected. 6.1.4 Secondary Winding: Star connected three phase terminal output. Centre point of secondary centre tapped as neutral (two leads). Five connections should be brought out i.e. one each for three phases and two neutral lines. 6.1.5 Secondary Voltage: The output Voltage between any one of the three phases and neutral line should be 230V, 50Hz/60Hz. 6.1.6 Electrostatic Screen. The transformers are to be fitted with an electrostatic screen (for isolation of primary and secondary winding) between each higher voltage winding and lower voltage winding. It is to comprise a single turn of copper or aluminum foil but must not form a closed loop. A connection is to be brought out so that the screen can be connected to the earth stud within the transformer casing. 7.0 Permissible Temperature Rise. 7.1 Winding. The Max. Permissible temp. rise is 80 0 C for Transformer of F class insulation when operating at Max. ambient air temp of 55 0 C. The Temperature rise shall be measured by resistance method. 7.2 Cores. The Temp. rise is in no case to reach such a value that there is risk or injury to any insulation material on adjacent parts. 8 Regulation. The regulation at 0.8 P.F should not be more than 3.3%. 9 Inrush Current. The saturated reactance of the primary winding of a transformer is not to be less than 4.2 Fp /K Ohm per phase. The Primary winding factor Fp=3 for a Delta connected Primary winding and K is the total KVA rating of a transformer as specified. In the TSPs. The saturated reactance is to be calculated as follows: 80 f N Xt = 2 A X 10 10 Ohm/ Phase Where LN : no. of turns in Primary Winding 7
A L F : Mean cross sectional area of the coil formed by the Primary winding (mm 2 ) : Length of the Winding (mm) : Supply Frequency (Hz) 10. Technical Requirements 10.1 Power Factor: 0.8 lagging 10.2 Performance: The Transformer shall be capable of giving its full rated output continuously or at any other specified loading cycle, within the normal ambient air temperature and steady state tolerance of electrical supply conditions, without exceeding the permissible temperature rise of its winding (i.e class F insulation 80 deg C) and regulation (3.3%) requirements as specified in clause 7.1 above. The tolerance of electrical performance of transformer are to comply with BS 3399. 10.3 Short Circuit Protection. The transformer is to be so designed that whenever being supplied at the upper steady state limit of input voltage, it can withstand a short circuit at the output terminals in accordance with the requirement of BS 3399. 10.4 Self Induced Noise and Vibration. Care is to be taken in the design and manufacture to ensure that airborne noise and structure borne vibrations produced by the transformer are reduced to as minimum as possible. Target figures for noise and vibration levels and methods of taking measurements are given in clause 0503 of specification NES 537. The self induced airborne noise level and vibration level not to exceed 60 db. The other general requirements for the design of electro technical equipment are given in specification NES 501. 10.5 Connecting cables. All connecting lead/cables used within the transformer enclosure should be of LFH type. 11 Construction. 11.1 Laminations. Laminations are to be of cold rolled grain orientated steel, the grade being selected to give minimum losses, size & weight. The laminations are to be tightly clamped to reduce noise emission and all bolts passing through the magnetic circuit are to be effectively insulated. 8
11.2 Insulation. The design of the Transformer should be F class. The insulation material of winding is to include a minimum thickness of 0.5 mm of mica or micanite or other approved insulation appropriate to the insulation class between one winding and any one of the following parts: (a) (b) (c) Core Another winding Earthed screen 11.3 Enclosure. The Transformer Enclosure shall be fabricated of MS sheet of 14 SWG. 11.4 Enclosure Protection. IP 23 Drip proof construction protecting water ingress up to ± 60 0 of angle. 11.5 Impregnation. All windings are to be impregnated with a thermosetting varnish by either of the following method: 11.5.1 Vacuum/pressure impregnation and bake, plus one dip and bake. 11.5.2 Hot dip and bake three times. 11.5.3 A smooth even finish of the windings is essential and an air drying finishing varnish may be applied after the impregnation process to achieve this finish. 12. Earthing. The transformers are to be fitted with a double ended threaded M 10 earth stud in accordance with NES 501. It is to be fitted through the casing of the transformer, adjacent the cable entry plate for the secondary winding, and labeled accordingly. The earth stud within the transformer case is to provide the earthing for Electrostatic screen and screening of cables, if fitted. 13. Terminal Arrangement. The transformers are to have their terminals sited above the core and accessible by removal of the top cover. The higher and lower voltage terminals are to be disposed so that neither the supply and outgoing cables, nor the terminal connections to the higher and lower voltage windings, cross each other or form inductive loops. The terminal arrangements must be capable of withstanding the through fault conditions. Bolted type terminals and crimping sockets of electrolytic copper are to be provided for all incoming & outgoing cables. 14. Cable Glands. The cable glands of mild steel for body and naval brass for nut for incoming and outgoing cable should conform to specifications 9
mentioned in DGS/EED/VI/1535/R6 and NES 514. The glands for incoming & outgoing cables are to be fitted on opposite ends and do not pass each other across the terminal board. The size of the cable gland shall be indicted at the time of approval of binding drawings. 15. Shock Standards. The transformer should conform to NSS II BR 3021 shock standards. 16. Vibration Standard. 5 33 Hz conforming to JSS 55555. 17. Cooling. Natural air cooled. 18. Shock Mounts. The transformer will be deck mounted on suitable shock mounts. The supplier should also supply suitable S/V mounts and quantity and pattern No. of mounts be indicated in the drawings. 19. Dimension & Weight. The max. overall dimensions & weight shall be kept to minimum without compromising the efficiency of the transformer. 20. Lifting Arrangement. Suitable lifting arrangement be provided on top of the transformer. 21. Efficiency. During the final stages of the temp. rise tests for the equipment, when temperatures are study, the output and input powers are to be measured(by wattmeter) to enable the equipment efficiency to be calculated. The efficiency is to be calculated during full load trials of the transformer in accordance with BS 3399. The efficiency shall be 97% and above. 22. Tests. The transformer is to be submitted for testing on approval of drawings within three months of the placement of order. The transformer will be subjected to following tests: 22.1 Type Test. One transformer from each rating is to be subjected to type testing as per Joint Services Specification JSS 55555. The type tests required to be carried out are listed at clause 0502 of NES 537. The transformers which are not required to be type tested are to be subjected to routine tests listed at clause 0508 of NES 537. 22.2 Environmental Tests. One of each rating of transformer will be tested for the following environmental tests: SNO. TEST SPECIFICATION TEST CONDITION/SEVERITY 10
(a) Vibration JSS 55555 Test 28 5 33 Hz (b) High Temperature JSS 55555 Test 17 55 0 C for 16 Hrs. Procedure 5, Test Condition G (c) Damp Heat JSS 55555 Test 10 40 0 C 95% RH for 16 Hrs. (d) Drip proof JSS 55555 Test 11 Vertical Water drip 1 mtr height for 15 min. (e) Mould Growth JSS 55555 Test 21 29 0 C 90% RH mould growth chamber for 28 days. (f) Bump JSS 55555 Test 5 1000 bumps 40G, 6m/sec (g) Shock/Impact As per BR 3021, NSS II grade. (h) Inclination/Tilt AS per NES 1004(Data sheet:36) (j) EMI/EMC MIL STD 461C/E As per laid down specifications 22.3 Test Results. The results of the type tests are to be compiled into a report. The results should include oscillographic records taken during the tests. The tests are to be carried out on rated voltage and frequency. 23. Sea Way Conditions. The equipment shall be capable of efficient and unrestricted operation without any deviation from its normal operating parameters under following conditions. 23.1 Ship Motion: (a) Roll Max. +/ 30 0 with 10 sec Operational (b) Pitch Max. +/ 10 0 with 20 sec Operational (c) List Max. 20 0 from vertical (permanent) Survival (d) Trim Max. 5 0 Survival 23.2 Environmental Conditions. The equipment offered for marine application shall achieve specified output and function smoothly under tropical conditions. It shall withstand air contamination through oil, salt and other contaminants associated with the marine environment. The equipment shall operate under the following environmental conditions: SNo. CONDITION NORMAL CLOSED DOWN (a) Temperature Storage 0 to 70 0 C 11
Operating 0 to 55 0 C (b) Relative Humidity Up to 100% at 38 deg C (c) Time Continuous Up to 48 hours. 24. Painting. Powder coating as per IS 5 code 632 grey colour. 25. Tally & Diagram Plate. 25.1 All tally and diagram plate shall be of aluminum oxidized. 25.2 A diagram plate indicating the details of connection is to be procured /affixed on each long side of transformer plate. 25.3 Size of tally plate, diagram plate, danger plate etc. and their letters shall conform to NES 723. 25.4 The information mentioned below are to be indicated on the tally plate: (a) (b) (c) (d) (e) (f) (g) (h) (j) (k) (l) (m) (n) (p) (q) (r) Rating in KVA No load voltage (HV & LV) Current in Amps(HV & LV) Percentage Impedance Total weight Frequency Class of Insulation Temperature rise C deg Type of cooling Purchase order and date Year of manufacturing Makers serial number Terminal plate indicating various output voltages Earth Terminal Danger tally voltage (RED) Connection diagram plate 26. Inspection Authority. DQA (WP)/DQAN 27. QAP. The manufacturer should submit a copy of Quality Assurance Plan to IHQ MoD (N)/DEE/DQAN for approval within four weeks of LOI. 12
28. Information to be supplied while Tendering. The manufacture should furnish the under mentioned details of transformer at the time of tendering: (a) Tender Drawing. Tender Drawings are to comprise three clear prints of the outline of the transformer, showing approximate overall dimensions and proposed fixing arrangements. The estimated total weight should also be given. (b) Voltage ratio at no load. (c) No load current (d) Full load losses(fixed, copper and total) (e) Efficiency (at full load UPF and half load UPF) (f) Regulation (at UPF and 0.8 PF lagging) (g) Method of voltage control to meet any special requirements for regulation which cannot be obtained by the inherent regulation of the transformer. (h) Maximum allowable temperature rise in deg C. (j) Output at abnormal ambient temperature, if applicable. (k) Class of insulation. 29. A brief specification of the equipment offered is to be submitted, together with confirmation that all the transformers will conform in all respects to the Procurement Specifications and relevant specifications or details of all proposed departures from the requirements of these documents. 30. Earth Screening Label. All double wound transformers which are self contained in their own enclosure are to be fitted with earth screening labels just below the tally plate to read as: SCREENED TRANSFORMER. 31. Binding Drawings and Documents. The format and content of documentation being provided should be as per JSS 0251 01 and EED S 048. In addition to the hard copy the documents be also supplied in the form of CD ROM. Documentation shall be presented as per the table below. (a) Equipment Manual 10 nos. (b) Installation specification 08 (c) CPIL/PIL 18 (d) Shop Trial Report 08 Test certificates (e) As fitted drawings (i) Velographs 02 13
(ii) Paper Prints 13 (f) CD ROM 02 31.1 Binding Drawings. Following binding drawings are to be submitted to the designated authorities for approval: (a) Overall dimension of the equipment (b) Mounting arrangement (c) CG of the equipment (d) Terminal connection details (e) Circuit diagram details as per clause 1002 of NES 535. (f) Part list indicating description, qty, part number, material and makers name etc. (g) List of tally plates. (h) Details of S/V mounts. (j) Details of Design Specifications. (k) Details of windings (Gauge, no. of turns, weight, insulating material etc.) 32. Product Support. The manufacturer should submit product support certificate for a period of 15 years. 33. On Board and Base & Depot spares. 33.1 On board Spares. An itemized list of OBS and special tools which will be supplied with the main equipment, are to be furnished along with the quotation for the main equipment. The OBS shall cater for onboard maintenance routines and possible repairs by ship s staff. The OBS should include the following: (a) All spares required for exploitation up to 2 years. (b) One set of general purpose maintenance tools. (c) One set of special tools required for disassembling /assembling of components to carry out repair by replacement. 33.2 B&D Spares. Base & Depot spares recommendation is to cover maintenance /overhaul requirements for 5 years including two refits. Itemised cost of B&D spares are to be forwarded with the main offer. 34. Governing specifications. Following are the relevant standards: (a) BR 3021 shock Requirements (b) JSS 55555 Environmental test methods for electrical & Electronic equipment 14
(c) EED/DGS/1535/R6 Cable Glands (d) IS 5 Powder coating painting (e) NES 723 Tally Plate (f) DEF STAN 08 107 Earthing (g) MIL STD 461 C/E EMI/EMC (h) DEF STAN 07 224 Material & finishes (j) DEF STAN 07 226 Electrical Testing (k) NES 581 Electronic components Practice. (l) NES 539 Guide to design the supply systems for Portable equipment (m) NES 535 Requirements for transformers for power Services. (n) NES 537 Requirements for testing of the transformers. (p) NES 501 General requirements for the design of electro technical equipment. (q) NES 511 Requirements of electrical testing of equipt. (r) BS 3399 Specification for transformers for use in ships. (s) BS 5629 Insulating varnish containing solvent. (t) IS Equipment Enclosure. (u) EED S 048/ Preparation of documents and drawings. JSS 0251 01 35. Warranty. The Transformer assembly is to be guaranteed for stipulated performance for 24 months after commissioning. The equipment supplied shall be warranted against defects arising due to malfunction through design faults, inappropriate material, bad production and non conformance to specifications. Any expense on account of repair/supply of spares against guarantee defects is to be borne by the supplier. 15