Eleven in one stroke

A tried and tested review of Omricon’s TESTRANO 600 by PCM Guatemala

Protección Control y Medición (PCM) is a leading service provider in Guatemala, providing their customers with electrical engineering services for primary and secondary equipment. The 12-man team specializes in commissioning and maintenance of electrical power substations and generation plants, and has vast experience in the execution and interpretation of electrical tests on various assets.

Manuel Martinez, Test Engineer at PCM Guatemala reports about his business, the daily challenges he faces and one recent, completely new experience that meets these challenges.

Transferred responsibility
”We have to verify that each asset is tested and that the results are satisfactory,” explains Manuel Martinez. The responsibilities have been transferred from the operator to the service provider, which puts them under considerable pressure: “We have to ensure that none of the tested assets will fail and our customers will not have any unforeseen failures in their substations and power plants. We are only successful when our customers feel satisfied with their equipment and with our service.”

“My typical tasks are to coordinate and execute electrical tests in the field and afterwards to create reports for each of the performed tests. For us, as a service provider, one of the biggest challenges here is to draw conclusions quickly and in the best way”, says Manuel Martinez. ‘Best’ in this case means the results obtained must be correct, complete and detailed enough to allow a comprehensive condition assessment for each test object.

Speed is the key
The most time-consuming task is the testing of power transformers. “Within a 12-month period, we tested on an average about 120 transformers and auto-transformers between 1 and 50 MVA, and rated from 4.16 kV to 230 kV”, states Manuel Martinez. He explains that considerable time is needed to setup the tests, re-connect between the different test jobs and for the measurement itself. “It takes, for example, about 4 hours to completely test a power transformer with 69 kV and 10 MVA.”

Speed is the key in this business. Hence, PCM Guatemala requested a live demonstration when they discovered the new time-saving three-phase power transformer test system TESTRANO 600 on the OMICRON website , which they then purchased. “We were impressed by the test system and its performance from the very first day. The device is very good, the software very user friendly and the training courses we received after buying our own device were excellent.”

One impressive day of testing
In April 2017, PCM Guatemala had scheduled a transformer testing job for one of their customers. “I have been working for PCM for almost 8 years now and through my work have come into contact with various devices. But I have never been able to test eleven power transformers within one day”, Manuel Martinez on working with TESTRANO 600.

“We started testing at 7 o’clock in the morning and had to test power transformers with 10 MVA and 22 kV including the de-energized tap changer (DETC),” he continues. “Numerous parameters were measured such as power/dissipation factor, capacitance, short-circuit impedance, excitation currents, turns ratio, and DC winding resistance. In between we also had to demagnetize the transformers; but at 4.30 pm, only 7 hours later, we were finished and all eleven transformers were ready to be reconnected to the grid.”

“I especially liked the demagnetization functionality as it reduces the residual magnetism to almost zero,” Manuel Martinez explains. “In consequence, the results of other subsequent diagnostic tests become more reliable and high inrush currents are avoided when a transformer is switched back into service.” The effort for demagnetization was minimal: no rewiring was needed as the setup of the previous test could be used again. It took only five minutes to completely demagnetize the transformer, and the test team could proceed with the next test job.

Reasons for being so quick
“In my opinion, the main reasons why we were able to test so many transformers respectively so quickly are easily explained. The device itself provides a new level of speed with which the measurements can be carried out. In addition, we were able to save a lot of time due to the three-phase testing capability and the easy connection concept. We could carry out almost all required tests using the same test setup; all of this with the greatest satisfaction,” Manuel Martinez adds.

New opportunities and perspectives
Compared to the 4 hours it took to test one transformer in the past, the latest testing experience with eleven transformers within one day set a new benchmark. From an economical perspective, this opens up entirely new opportunities for PCM. “Due to the usage of TESTRANO 600, we were able to achieve considerable cost savings, which allowed us to offer better prices to our clients, resulting in probably new orders,” explains Manuel Martinez.

“I estimate the investment in TESTRANO 600 will be amortized in a span of one year”. Thus, PCM is planning to invest in a number of additional test sets in the future. “I think our customers will also appreciate this investment as it also reduces the time their assets are offline.”

This product feedback was submitted by Omicron Energy Solutions Pvt.ltd.