Suggested technical specifications for power transformers and reactors (66 kV and up)

Essential and very expensive

In a power system, the transformer and the reactor are two assets that are both essential and expensive. The rise in energy consumption will necessitate not only an increase in the capacity for transformation but also an increase in the requirement for reactive compensation. When it comes to the efficient running of a power system, factors such as the reliability and availability of crucial assets play a significant part.

It is imperative to prioritize enhanced design, rigorous quality control throughout the production process, utilization of appropriate components and accessories, diligent maintenance, and strict adherence to safety protocols when operating these critical assets.

Transformers and reactors often experience premature failure, primarily attributed to several factors including substandard raw materials, inadequate workmanship, and manufacturing techniques. Additionally, the stresses encountered during operation, such as frequent system faults, overloading, environmental influences, unexpected continuous operating voltage, and overvoltage stresses, contribute to their diminished longevity.

Furthermore, poor maintenance practices further exacerbate the issue, resulting in these electrical components failing well before their anticipated lifespan of approximately 35 years.

The potential economic consequences resulting from the malfunction of critical equipment are substantial, mostly due to the considerable expenses and extended timelines associated with the procurement, manufacture, and installation processes. The extended duration required for repairs is a significant issue in numerous instances of transformer/reactor failure.

There is a lack of standardized practices across utilities regarding the technical specifications of transformers and reactors. Currently, transformers and reactors of the same rating/class are being designed in varying ways, even when intended for the same customer.

Manufacturers carefully evaluate the design of their products for consecutive bids, taking into account the prevailing market conditions, even when the parameters remain the same.

Figure 1 – Typical transformer factory drawing (click to zoom)

As a consequence, there is an unwarranted escalation in the duration of design and manufacturing cycles, expenses, labor requirements, and inventory levels. Given the aforementioned circumstances, it became imperative to tackle this matter by formulating a standardized and universally accepted design and engineering specification for transformers and reactors.

This specification would encompass the most effective methodologies employed by different utilities, incorporate the latest technological advancements, and account for future trends. Consequently, utilities and manufacturers would adhere to this specification as a guiding framework.

The standardization process is expected to yield several advantages, which include the following:

1. The streamlining of the procurement process and the reduction in delivery time would lead to the early completion of the project.
2. The utilization of standard designs would eliminate the need for frequent design reviews.
3. The implementation of standard ratings and standard civil foundation blocks would enhance the interchangeability of transformers and reactors from different manufacturers.
4. The use of standard fittings and accessories.
5. The reduction in inventory requirements.

This document is intended for the use of new transformers and reactors with a voltage class of 66 kV and higher. The document does not provide information on transformers that are appropriate for use in Static Var Compensator (SVC), Static Compensator (STATCOM), traction, welding, testing, mining, furnace, and inverter applications for Renewable generators.

This document exclusively addresses the technical aspects related to the manufacturing, transportation, erection, testing, commissioning, and condition monitoring of transformers/reactors. The utility has the authority to set the commercial aspects, contractual conditions, and scope of works for the OEM/contractor based on its specific requirements and established practices.

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