What is an Inverter Transformer?

Solar power plants are like green superheroes, but they rely on important parts to turn sunlight into usable energy. One crucial part is the inverter transformer. The inverter transformer component takes the electricity made by solar panels (it’s called direct current or DC) and turns it into the kind of electricity that powers our homes and industries (called alternating current or AC). In simpler terms, it changes solar power into the energy we can use every day. This article will explain more about the inverter transformer and why it needs regular check-ups to work perfectly.

Why Solar Power Plants Need a Monthly Inverter Transformer Maintenance Checklist?

Solar power plants require an inverter transformer maintenance checklist to ensure optimal performance and longevity. Regular maintenance is essential for reliability, efficiency, and maximizing the return on investment in renewable energy.
Crafting a thorough inverter transformer preventive maintenance checklist for solar plants and inverters is crucial for extending the system’s lifespan and optimizing your return on investment. Include routine operational checks, maintenance tasks, inspections, and prompt repairs or replacements in this checklist to guarantee peak performance.

Preventive Maintenance for Inverter Transformers

Regular preventive maintenance for inverter transformers is necessary for their long-term reliability and performance. Preventive maintenance involves daily inspections and time-specific inspections. But here, we will discuss only the time-based activities to ensure the effective working of the transformer. The most crucial factor here is the maximum desired load (LMAX). 

LMAX = P/Power Factor


P = real power from the transformer

Preventive maintenance enhances reliability, minimizes downtime, optimizes energy output, and contributes to the overall efficiency of solar power plants. Maintaining inverter transformers, shown in Figure 1, is also essential in an era where clean energy sustainability is important.

Figure 1: Inverter Transformer

Critical Factors in Inverter Transformer Selection

While selecting an inverter transformer for your solar power plant, you must consider a few points for your equipment’s better performance and lifespan. Mentioned are a few points that must be considered:

  1. Current Density
  2. Flux Density
  3. No Load Loss and Full Load Loss
  4. Power Factor Level
  5. Maximum Desired Load
  6. OEM Credentials

Load Requirements for Solar Plants

First, you need to calculate load power. This can be calculated easily by connecting all the devices and systems the inverter transformer will serve. Now, apparent power (PA)in KWA (Kilovolt-amperes) can be calculated using the formula:

PA = Load Power / Power Factor

Now you can calculate the transformer rating using the formula:

VA =PA / (√3 x VP x IS)


Vp is the Primary Voltage

IS is Secondary Current

Finally, IFL (Full Load Current) can be calculated using the above values:

IFL = PA / (√3 x VS)

Incorporating Preventive Maintenance in Inverter Transformers

Now, we step into maintaining your Inverter transformer if you have already installed it. But, if you desire to get more out of it, go through this article for the steps to enhance the efficiency of your equipment with our undermentioned guidelines.

Monthly Inspection Checkpoints

Monthly Inspection Checkpoints are the backbone of maintenance routines. These essential examinations ensure critical systems and equipment’s continued reliability and performance. Before you go into inspection of such critical equipment with such a high voltage, make sure that it is completely isolated as mentioned below:

Activities Before Inspection

  1. First, isolate the equipment from the concerned department (Electrical in this case)
  2. Get a duly signed work permit from the concerned department and maintenance activity manager.
  3. Ensure the equipment is completely isolated by starting it manually.
  4. Discharge the power terminals safely.

Preventive maintenance Checklist

  1. Checking the Oil Level in the conservator tank
  2. The radiator Valve should be in open condition
  3. The Conservative Valve should be in open condition
  4. Ensuring Proper Ventilation of the Buchholz relay
  5. Ensuring no air gap near the HV/LV cable gland
  6. Checking support of HV/LV cable
  7. Adjusting low tension in the HV/LV cable gland
  8. Inspecting air vents properly
  9. Ensuring no oil leakage in the transformer body
  10. Ensuring proper earthing of respective cables for men’s safety
  11. Verify Inverter Bus Duct is entirely waterproof.
  12. Ensuring transformer surroundings are clean and dust-free


In short, the inverter transformer is a crucial part of solar power plants, connecting sustainability and innovation. It is critical in turning solar-generated DC electricity into usable AC power. However, the reliability and lifespan of these transformers depend on regular maintenance. Monthly inspections are vital for keeping the transformer in good shape. These monthly checklists cover various aspects to ensure the transformer performs well. Solar power plants can ensure a constant energy supply by following these inspection guidelines and prioritizing safety.

You can download a sample here- Download Inverter Transformer PM Monthly Check Sheet


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