Objectives

The primary objective is to engage a qualified service provider to conduct comprehensive electrical testing on a single 132/11 kV, 20 MVA power transformer at Cygnus Substation. The procurement seeks to validate transformer integrity, ensure operational reliability, and maintain compliance with international engineering standards while fulfilling municipal supply chain governance requirements.

Scope of Work

• Provide all specialized test equipment and competent personnel required to perform transformer diagnostics.
• Execute a predefined sequence of electrical, insulation, and impedance tests on HV/LV windings, bushings, and associated components.
• Deliver unprocessed raw test data to the municipality for independent review.
• Generate a detailed final report encompassing test timing, ambient and oil temperatures, humidity, instrument specifications, applied electrical parameters, test durations, and benchmark comparisons.
• Submit calibration certificates for all testing instruments (valid for less than twelve months).
• Implement and document safety procedures fully aligned with Occupational Health and Safety legislation.

Technical Requirements

All testing must adhere to IEC, IEEE, and IS standards. Mandatory technical deliverables include:

• Tan Delta Testing: Performed at 10 kV on HV windings, LV windings, inter-winding insulation, and HV/LV bushings.
• Excitation Current: Open-circuit measurement to assess magnetic core performance.
• Turns Ratio: Verification across all tapping positions at 10 kV.
• Leakage Reactance/Impedance: Short-circuit testing to evaluate voltage regulation and fault tolerance.
• Sweep Frequency Response Analysis: Frequency-domain diagnostic scanning.
• Insulation Resistance: Dielectric integrity assessment.
• Winding Resistance: Static and dynamic measurements to detect conductor degradation or poor connections.

Skills & Experience Requirements

Evaluation utilizes a weighted scoring matrix requiring a minimum threshold of 80%. Essential qualifications include:

• Domain Experience: Documented three to four years of hands-on experience specifically in power transformer testing.
• Project Track Record: Submission of relevant completed contracts (three or more awards yield maximum points; fewer than two or absence results in zero allocation).
• Professional Registration: Active ECSA registration as a Professional Technician, Technologist, or Engineer.
• HV Authorization: Valid Responsible/Authorised Person certificate for High Voltage Systems.
• Specialized Training: Accreditation or certification in Electrical Protection disciplines or Power Transformer systems.
• Industry Classification: CIDB Grading 6 or equivalent capability rating.
• Administrative Compliance: Central Suppliers Database registration, Tax Clearance Certificate, Compensation Fund Letter of Good Standing, and completed preferential procurement documentation.

Notes on Specialized Terms

• Sweep Frequency Response Analysis (SFRA): A highly sensitive diagnostic method that detects mechanical deformation, winding displacement, or core movement by analyzing how the transformer responds to varying electrical frequencies.
• Tan Delta (Dissipation Factor): Quantifies dielectric losses within insulation; rising values typically signal moisture absorption, chemical degradation, or thermal aging, enabling predictive maintenance.
• CIDB Grading 6: A South African construction industry classification denoting a contractor’s verified financial stability and operational capacity to manage medium-value engineering contracts.
• ECSA Registration: Mandatory licensing by the Engineering Council of South Africa, ensuring technical personnel meet nationally mandated competency, ethics, and continuing professional development standards.
• MBD Forms: Standard Municipal Bid Documents legally required to declare conflicts of interest, verify past contractual performance, confirm tax compliance, and certify independent bidding practices.