Part 3: Transformers & Forms

Schedule A3 - Communication Requirements

With regards to the communication link between the 22kV switchgear Panels (Upper LV control compartment) and the CEB SCADA facilities, the required signals to be provided with proper labelling in a dedicated electrical panel located in the CEB side of the switchgear room are:

1. Status and Alarms (dry contacts)

2. Control Signals (through potential free contacts)

Note:
(i) The information given above in 1(i), 1(ii), 2(i) and 2(ii) is applicable for the load break switches in ALL the CEB 22kV incoming cubicles as described in item 1.
(ii) The Circuit Breaker here refers only to the CEB Circuit Breaker as described in item 3.

For MSDG implementation, layout of the communication system shall be as per Annex 9.

Schedule A4 - Safety Procedures regarding the operation of High Voltage Switchgear

In order to ensure the safety of personnel while operating or working on High Voltage Switchgear installed for the purpose of supplying electricity to the Client's premises, the following requirements and procedures shall be adhered to:

1. To comply with Section 7(2) of the Occupational Safety & Health Act 2005 (OSHA 2005) which states "Where the total power used or generated by machinery installed at any place of work exceeds 750 kilowatts, the employer shall employ a Registered Professional Engineer to be in general charge of all such machinery".
2. The Client shall appoint and train competent person/s who shall be responsible for the operation of the High Voltage Switchgear. He/they shall be fully conversant with the electrical set-up, including that of the Switchgear belonging to CEB. The contact details of the competent person(s) shall be affixed within the CEB side of the switchgear room. The CEB shall be immediately notified of any change in the contact details.
3. An up-to-date schematic diagram of the switchgear set-up shall be displayed in the switchgear room.
4. All switchgear panels shall be clearly numbered and labelled.
5. Before any work can be performed on either the CEB side or Client side of the switchgear panel appropriate switching operations shall be carried out by the respective competent person in the presence of his respective counterpart. The competent person performing the operations shall certify the operations carried out on the approved Certificat de Consignation form and shall remit the original to his counterpart, who may then proceed with the work in accordance with the Safety Rules.
6. In case of private generation, the client shall ensure that his system is completely isolated from CEB system.
7. For MSDG, the provision of the MSDG Grid Code shall be followed.

PART II: OUTDOOR DISTRIBUTION TRANSFORMERS

Schedule A5 - Outdoor Distribution Transformers (with Plug-in Bushings)

The Distribution Transformer shall preferably be of the outdoor type, ground-mounted and cover the following capacities:

• Item 1 - 500 kVA
• Item 2 - 1000 kVA

Characteristics of the Distribution Transformer

* Customers wishing to purchase cast resin transformers (for indoor use), should submit all detailed characteristics of the proposed units including Type Test Report from an independent and recognised institution.

Other Requirements

The transformer shall be:

1. Supplied with oil as per specifications contained in Schedule A6 – Mineral Insulating Oil for Transformers.
2. Fitted with:
   • (a) Oil level indicator
   • (b) Oil filling hole with plug
   • (c) Lifting lugs
   • (d) Earthing terminal for tank
   • (e) Drain plug with sampler cock
   • (f) Diagram and rating plate
   • (g) Terminal marking plate
   • (h) Off-circuit tap changer with ± 2 ½% and ± 5% taps (as per the above-mentioned standard)
3. Supplied with detachable top yoke to allow removal of windings for repairs.
4. Externally hot dip galvanised to BS EN ISO 1461.
5. Designed for ground mounting with rollers.
6. Designed with a bolted cover.
7. Designed with the following terminations:
   • (a) HT side - 3 plug-in type bushings rated 200A, 24 kV suitable for the reception of elbow plug-in connector
   • (b) LT side - 4 bushings and associated copper cable terminals having the following characteristics:
     • (i) be of vertical type.
     • (ii) bottom part to be threaded onto the bushing rod and tightened by two side bolts.
     • (iii) have a top palm, undrilled, and of dimensions (width x height):
       60 mm x 70 mm for 500 kVA
       60 mm x 130 mm for 1000 kVA

Standards

• IEC 60076 - Power Transformers
• BS EN ISO 1461 - Hot dip galvanised coatings on fabricated iron and steel articles (specifications and test methods)

Guaranteed Particulars: All relevant data shall be supplied where applicable by filling in the Schedule of Guaranteed Particulars – Schedule B5, and dimensional drawings of the transformer shall also be submitted.

Schedule A6 - Mineral Insulating Oil for Transformers

The insulating oil shall be for use in transformers and switchgear and shall comply to IEC 60296 and 60156 or equivalent.

The oil shall be free of PCB and be of such quality that it shall not require any user precautionary labelling as defined by the EEC Dangerous Substances Directive 67/548/EEC.

The CEB prefers that the oil be of Uninhibited Type.

The polycyclic aromatic content by IP 346 shall be maintained below 3%.

Guaranteed Particulars: All relevant data shall be supplied where applicable by filling in the Schedule of Guaranteed Particulars – Schedule B6.

GUARANTEED PARTICULARS FORMS

Form Submission Requirements

All Guaranteed Particulars forms (B1-B6) must be:

1. Completed in full with accurate technical specifications
2. Verified by a Registered Professional Engineer
3. Submitted to CEB for approval before equipment procurement
4. Accompanied by manufacturer's technical datasheets
5. Updated if any specifications change during implementation

Typical 22 kV Switchgear Room Layout

Summary - Annex 7 Compliance Checklist