ZIMBABWE ELECTRICITY TRANSMISSION & DISTRIBUTION COMPANY
A Subsidiary of ZESA Holdings
REQUEST FOR COMPETITIVE QUOTATIONS (RFQs)
Tenders are invited from registered and reputable Suppliers/Companies for the Supply and delivery of transformer oil PR 30032021 to ZETDC Northern Region.
RFQ NUMBER | QUANTITY | DESCRIPTION OF REQUEST FOR QUOTATION (RFQ) | CLOSING DATE |
67/2024 |
10 DRUMS |
TRANSFORMER OIL TOP UP PIL CHANGE AND MAINTENANCE FOR TEGWE SUBSTATION |
03-05-2024 |
Quotations must be enclosed in sealed envelopes and clearly endorsed on the outside with the advertised RFQ number, the description of the Request for Quotation (Purchase), the closing date and must be posted in time to be sorted into Post Office Box No. 293 Chinhoyi or delivered by hand to the Tender Box ZETDC Northern Region Stand No. 5310 North Drive Chinhoyi or can be emailed on the following email addresses: nroprocurement@zetdc.co.zw on or before 10:00 hours on 03 May 2024.
Tenders should be accompanied with the following documents;
- Current tax clearance.
- ZETDC’s payment terms are strictly after delivery
- Prices should be in USD dollars payable in USD NOSTRO
- Bid validity of 20 days
- Delivery should be ex-stock/within 5 working days
- Proof of registration with Procurement Regulatory Authority of Zimbabwe [PRAZ] in relevant category.
Late bids will not be considered.
Tenderers are free to witness the opening of tenders on the closing date and time. ZETDC does not bind itself to accept the lowest or any tender and reserves the right to accept the whole or part of any tender.
For further details please contact The Procurement Office on telephone numbers 067-23784/25735-9 /23071-3 /0776 909760/0773 452 841/0772 425 825
Emails; nroprocurement@zetdc.co.zw,
Visit our website@www.zetdc.co.zw
GENERAL MANAGER (NORTHERN)
ZIMBABWE ELECTRICITY TRANSMISSION AND DISTRIBUTION COMPANY
SPECIFICATION No.DS18102021TXFOIL
FOR NEW TRANSFORMER OIL
Table of Contents
2.0 PARTICULARS OF ELECTRICAL SYSTEM.. 3
3.0 PARTICULARS OF THE ENVIRONMENT. 4
4.1 Properties of new transformer oil 4
5.0 Transportation and storage of new transformer oil 5
5.1 Electrical discharge during transportation and storage. 5
5.2 Earthing of Transportation and Storage equipment 5
5.2.1 Earthing of Transportation Equipment 5
5.2.2 Earthing of Storage Tanks. 5
6.0 TECHNICAL GUARANTEE SCHEDULE OF COMPLIANCE WITH ZETDC SPECIFICATIONS. 6
1. SCOPE
This specification calls for supply and delivery of new transformer oil. The details of the transformer oil are as specified in Schedule of Requirements.
The supplier shall state whether or not the transformer oil is produced under license, in which case license holders name shall be stated.
2. PARTICULARS OF ELECTRICAL SYSTEM
The oil shall be used under the following system conditions: –
- Transformers with sizes from 10kVA to 140MVA.
- Operated at 50Hz variable between plus or minus 2.5%
- Maximum system voltages of 400kV (+- 10%).
- Earthed so that the earth fault factor will be less than 1.5 at any location.
- Maximum Short circuit current of 31.5kA for both 33kV and 11kV networks.
3. PARTICULARS OF THE ENVIRONMENT
The transformer oil shall be capable of operation under the following environmental conditions: –
- At an average altitude of 1 500m above sea level.
- Ambient air temperatures never above +45°C or below -10°C with a maximum daily average of 35°C.
- Exposed to direct tropical sun.
- Subject to wind pressure not exceeding 700N/mm square.
- Humidity 13gm/mᵌ absolute and 54% relative before storms with vapour pressure
17mm hg.
- Equipment will operate within the tropics and is subject to sudden ambient air temperature changes of the order of 10 degrees centigrade occurring at the onset of rain, but the barometric pressure at any given place does not vary by more than approximately 10mm mercury. Frequent and severe lightning storms occur during summer months, with isoceraunic levels varying between 50 and 110 thunderstorm days per annum.
- Particular attention should be paid in the design of all equipment to ensure that there is no damage to working parts or insulation through the ingress of dust, insects, vermin which are prevalent for long periods in the year.
4.0 TECHNICAL REQUIREMENTS
The following standards are applicable in this specification:
IEC 60296.
Where there is conflict between ZETDC specifications and the standards, ZETDC specifications shall prevail.
4.1 Properties of new transformer oil
The new transformer oil should conform to the following:
- The breakdown/dielectric strength shall be 60 kV or better using a 2.5 mm gap cell.
- The moisture at 20 degrees Celsius shall be 30 PPM or less.
5.0 Transportation and storage of new transformer oil
Transformer oil is an inflammable liquid and thus care should be taken during transportation and storage. Naked flames and/or highly inflammable substances should be kept at a distance from the transformer oil so as to avoid fires that could destroy the transformer oil.
5.1 Electrical discharge during transportation and storage.
Material used for containers for storage and transportation of transformer oil should have a relatively low affinity to accumulation of electrical charge/electrostatic (Q in coulombs), so as to avoid electrical discharge, which can result in sparks and causes fires.
5.2 Earthing of Transportation and Storage equipment
5.2.1 Earthing of Transportation Equipment
Transportation tanks/equipment for the transformer oil should be equipped with earthing equipment so that during stopover, the tank/equipment is earthed, by driving and earthing electrode into the earth, so that electrostatic charge that would have accumulated during travelling (due to ionisation of surrounding air and therefore charge the container/tanker electrically) can be discharged to earth without causing electrical sparks which can start fires.
5.2.2 Earthing of Storage Tanks
All Storage tanks/equipment should be solidly earthed, to avoid sparks that may arise as a result of the accumulation of electrostatic charge which can spark and start fires.
5.2.3 Packaging
The oil shall be packed in 210Litre drums.
6.0 TECHNICAL GUARANTEE SCHEDULE OF COMPLIANCE WITH ZETDC SPECIFICATIONS
Bidders shall complete the Table shown below, indicating the guaranteed values for the new oil in compliance with IEC 60296.
Sl. No | Description | Unit | Required | Guaranteed Value |
Function: | ||||
1 | Kinematic Viscosity | |||
@40°C | mm2/sec | Max. 16.5 | ||
@ (-) 30°C | Max. 1800 | |||
2 | Pour Point | °C | Max. (-) 40 | |
3 | Water Content (PPM) | mg/kg | ≤ 30 | |
4 | Breakdown Voltage | IEC 60156 | Min. 60 kV as delivered
|
|
5 | Density @20°C | KG/dm3 | Max. 0.895 | |
6 | Dielectric Dissipation Factor @ 90°C & 40 to 60 Hz | Max. 0.005 | ||
7 | Appearance | VISUAL | Clear, free from sediment & suspended matter | |
8 | Acidity | mg KOH/gm | Max. 0.01 | |
9 | Inter Facial Tension | MN/m | Min. 40 | |
10 | Corrosive Sulphur | Non Corrosive | ||
11 | Potentially Corrosive Sulphur | Non Corrosive | ||
12 | DBDS (Dibenzyldisulphide) | mg/kg | Not Detectable (<5mg/kg) | |
13 | Inhibitors of IEC 60666 | % | Inhibited Oil; (0.08% to 0.4%) | |
14 | Metal Passivator Additives | mg/kg | Not Detectable | |
15 | 2 Furfural Content | mg/kg/gm | Not Detectable | |
16 | Oxidation Stability | |||
A) Total Acidity mg KOH /gm
B) Sludge % C) oxidation stability, minutes, min. |
Max. 1.2
Max. 0.8 220 |
|||
17 | Flash Point | °C | Min. 135 | |
18 | PCA Content | % | Max. 3.0% | |
19 | PCB Content | mg/kg/gm | Not Detectable |