High Efficiency Distribution Transformers

Distribution transformer replacement

What are the decision factors in replacing an operating distribution transformer with a new one

Usually, distribution transformers are only replaced after failing.

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Transformers in power distribution networks

Why do we need transformers? The answer is simple: impedance. If power losses in electricity distribution networks are to be kept within reasonable limits, then large amounts of electric power have to be transmitted across long distances at the highest feasible voltage. In absolute terms, the higher the trans-mission voltage, the smaller the current and hence the smaller the (resistive) power losses in the transmission cables. But increasing the transmission voltage also reduces a given power loss in relative terms.

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ATP/EMTP Study of Ferroresonance Involving HV Inductive VT and Circuit Breaker Capacitance

Ferroresonance is a phenomenon usually initiated by transients in power networks resulting from, for example, switching operations or ground faults. Non linear behavior of the core of an inductive voltage transformer results in magnetic saturation. Long-lasting ferroresonant states are dangerous to equipment due to prolonged overvoltage and large overcurrents in HV windings. In the present article, numerical simulations of the ferroresonance phenomenon in a HV inductive VT are presented.

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Global MVA Demand for Power and Distribution Transformers

Traditionally published reports have provided sales value data (historic and forecast) for various types of transformers, international trade values and regional market share data of the major suppliers. For most of the four decades transformer prices have been depressed and the relationship between sales value and sales volume has remained fairly constant and market value information was sufficient for most international marketing purposes.

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Estimation of the energy losses of transformers at wind turbines

Often windturbines in the range between 300 kVA up to 3000 kVA are connected to the MV grid by a distribution transformer. Very often it is easy to measure the electricity on the LV side of the transformer, which is connected to the windturbine. Since this is not the actual point of connection with the grid, it is needed to make an estimation of the energy losses due to the transformer.

As can seen from the figure above the measured electricity at the location of the meter equals to Ewind, while the actual delivered energy to the grid equals Edelivered. The difference between them are the losses caused by the transformer (strictly the cables should also be included). To calculate the electricity delivered it is necessary to make an estimation of the losses of the transformer.

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