1. Background:
The Mozambique Transmission Company – MOTRACO – is a limited liability company incorporated in the Republic of Mozambique in 1998. The company is a joint venture of Electricidade de Moçambique (EDM), Eskom Holdings (Eskom), and Eswatini Electricity Company (EEC). MOTRACO was created as a vehicle for co-operation with the primary objective of building, owning, operating, maintaining the transmission system, and supplying electricity to the Mozal aluminium smelter in Mozambique, and wheeling power to EEC and EDM.
2. Contextualization and Scope of Work:
2.1. Capacitor Bank 2 Breaker
MOTRACO intends to hire a qualified contractor to provide repair services for the Alston GL316 400kV Shunt Capacitor bank 2 Circuit breaker manufactured in 2002, which has experienced operational issues. Recent recordings indicate that the red pole of the circuit breaker is sometimes too slow, causing the current protection system to operate and trip the capacitor bank.
Additionally, the circuit breaker is 20 years old, raising concerns about its aging and overall reliability, and it is operated daily, hence requires urgent attention.
The scope of work is presented below:
- Infrared Scanning.
- Trip Testing (as per Secondary plant/protection scheme requirement).
- Condition of mechanism.
- Condition of operating assembly.
- All defects and failures repaired.
- All settings changed or corrected.
- All test results.
- Auxiliary timing.
- Contact burn measurement.
- Circuit breaker damping.
- SF6 gas analysis.
- “Low gas” alarm and “Inhibit” alarm.
- Lubrication of mechanism, trip, and close assembly.
2.1.1 Breaker Nameplate
| Attribute | Details |
|---|---|
| Manufacture | Alston |
| Type | GL 316 |
| Mechanism Type | Spring |
| Voltage | 420kV |
| Amps | 3150 |
| KA | 40kA |
| Year of Manufacture | 2002 |
| SN | 108180002001 |
2.2. Mozal 3 TRF Pantograph Isolator
MOTRACO intends to hire qualified contractors to repair and maintain the 400kV Mozal TRF 3 pantograph isolator. The isolator failed to close two phases upon command from the control room, and manual force was required to operate it. A visual inspection revealed significant signs of humidity and rust inside the operating mechanism box. The repair is required to restore the isolator to full operational condition.
The scope of this repair work includes, but is not limited to, the following:
- Resistance Test from clamp to clamp.
- Remove jumper clamps.
- Remove the current path from the post insulator.
- Inspect the condition of the male and female contacts.
- Inspect the condition of the transfer contacts.
- Perform a contact pressure test.
- Clean and lubricate contacts.
- Refit current paths on post insulator.
- Inspect and lubricate the sealing ring, replaced if damaged.
- Maintain and refit the jumper clamps (torque bolts to spec).
- Clean, inspect, and lubricate the inter-phasing and inter-connecting rods.
- Clean and inspect the post insulator.
- Check alignment and re-align if necessary.
- Clean and lubricate the isolator mechanism.
- Ensure that the auxiliary switch operates correctly.
- Check that the isolator operates correctly.
- Measure motor current.
- Perform a contact resistance test from clamp to clamp.
- Inspect the flexible earth on the vertical drive shaft.
2.2.1 Isolator Nameplate
| Attribute | Details |
|---|---|
| Manufacture | Actom |
| Type | P300-422540 M/D |
| Year of Manufacture | 2002 |
| SN | 3050605/1 A-B-C |
3. Format of Proposal:
The proposal must be detailed and present the following:
- Material list to be used by the contractor;
- Cost of labour;
- Any other applicable costs.
Bidders shall submit the following documents:
- Company profile;
- Track record and experience on similar work, including reference letters;
- Company registration documents and supporting documents;
- ESKOM – Northeast Grid Authorisation for the person who will supervise and take permit.
4. Clarifications:
All clarifications shall be submitted by email to MOTRACO to the attention of:
- Name: Virgilio Laisse, Operations Engineer
- Email: Vlaisse@motraco.co.mz
- Cc: esitoe@motraco.co.mz
5. Closing Date:
The proposals must be submitted no later than 03:00 PM on October 11th, 2024.