How do power transformer harmonics and losses affect the grid stability and reliability?

1 What are harmonics?

Harmonics are distortions in the voltage and current waveforms caused by nonlinear loads, such as electronic devices, variable speed drives, or arc furnaces. Harmonics can create multiple problems for power transformers, such as overheating, insulation degradation, noise, vibration, and reduced lifespan. Harmonics can also affect the power quality and stability of the grid, leading to voltage fluctuations, flicker, resonance, and interference.

2 What are losses?

Losses are the energy dissipated by the transformer during its operation, mainly due to the resistance of the windings and the magnetic properties of the core. Losses can be classified into two types: load losses and no-load losses. Load losses vary with the current flowing through the transformer, while no-load losses occur even when the transformer is idle. Losses reduce the efficiency and output of the transformer, as well as generate heat and increase the cooling requirements.

3 How to measure harmonics and losses?

Harmonics and losses can be measured using various methods and instruments, such as power analyzers, meters, sensors, or software. Harmonics can be quantified by the total harmonic distortion (THD) or the individual harmonic components of the voltage and current. Losses can be calculated by the difference between the input and output power of the transformer, or by the specific loss factors of the core and windings.

4 How to reduce harmonics and losses?

Harmonics and losses can be reduced by applying different techniques and solutions, depending on the source and level of the problem. Harmonics can be reduced by using filters, reactors, capacitors, or active power conditioners, which can block, absorb, or compensate for the harmonic currents. Losses can be reduced by using high-efficiency transformers, low-loss materials, optimal design, or smart control systems, which can adjust the output and cooling of the transformer according to the load and temperature.

5 How to prevent harmonics and losses?

Preventive maintenance is a key strategy to prevent harmonics and losses from affecting the transformer and the grid. Preventive maintenance involves regular inspection, testing, monitoring, and cleaning of the transformer and its components, as well as identifying and correcting any faults or defects. Preventive maintenance can help detect and prevent harmonics and losses before they cause serious damage or failure, as well as optimize the performance and lifespan of the transformer.

6 How to plan preventive maintenance?

Preventive maintenance should be planned according to the specific needs and conditions of each transformer and grid. Preventive maintenance should follow the manufacturer's recommendations, as well as the standards and regulations of the industry and the utility. Preventive maintenance should also consider the operational history, loading profile, environmental factors, and risk assessment of the transformer and the grid. Preventive maintenance should be scheduled and performed by qualified personnel, using appropriate tools and methods.