Power transformer maker relies on Yokogawa power analyzer


Yokogawa’s WT5000 Precision Power Analyzer has helped Società Elettromeccanica Arzignanese match its efficiency guarantee with actual transformer performance.

Founded in 1959, SEA supplies high-value assets which are expected to provide a return over decades. Quality, durability, safety and reliable performance are therefore key characteristics that customers are looking for when they specify a new transformer or reactor.

Transformers play a crucial role in the transmission and distribution of electrical energy; they precisely regulate the voltage of the electricity supply as it is transmitted from power stations to homes, offices, factories and high power consumers, such as railways. There is always some power loss when one voltage level is changed to another. In a transformer operating at transmission-network voltages of tens of thousands of volts, the loss of even a fraction of 1% of the converted power can result in losses of many thousands of Watthours of energy every year.

A primary requirement is therefore to make a transformer as efficient as possible to reduce both the financial loss and the emissions of greenhouse gases, and other pollutants, when generating the extra energy required to make up for the power lost in transmission.

The efficiency of a transformer, needs to be carefully verified before shipment to the customer; the terms and conditions of the sale of a transformer typically specify financial penalties running to tens of thousands of Euros if it fails to operate as efficiently as specified by the manufacturer.

The measurement of a transformer’s efficiency, according to the IEC60076-1 industry standard, requires an instrument capable of measuring voltage, current, phase and power (W) over a range of power factors from 1 down to 0.01.

SEA entrusts these critical transformer power measurements to the Yokogawa WT5000, the world’s most accurate precision power analyzer, which offers an AC power measurement accuracy of ±0.03% at 50 / 60 Hz and provides performance guarantees from 1% to 130% of the selected voltage and current ranges. High accuracy measurements at very low power factors particularly requires a power analyzer to possess very low uncertainty for its internal phase shift. This along with all other influences are fully specified for the WT5000, which makes it ideal for the measurement of transformer losses under no-load conditions.

Renato Franco, Testing Manager at SEA, says: “When buying an instrument intended for use over a period of many years, measurement stability is as important as accuracy.” Continuing he says: “Evidence from accredited calibration shows that the instrument not only provides us with the accuracy we need, but also maintains its performance over many years of use – this is a very important reason for us to choose the WT5000.”

SEA’s customers therefore benefit from the highest possible specified operating efficiency, which in turn gives the manufacturer a competitive edge in the market, since claimed efficiency is one of the most important factors affecting the transformer buyer’s choice of product.

Renato Franco of SEA concludes: “For us, it is vital to deliver a product that matches its high design specifications. By using the proven accuracy and stability of the WT5000 to both specify our transformers and to check their individual performance, we are confident that our customers are really getting what they are paying for.”