A Sneak Peek Into Stationary Engines’ Reactive Loadbank Testing

A reactive load bank test of the power generation system of a facility can in fact stimulate the response of the system to the changing pattern of the load.

Ideally, a combination of resistive and reactive load banks is used for testing the engine generator set, at its designated power factor, which generally remains to a power factor of 0.8. The reactive component of the resulting load will contain a current that lags that required voltage. Thus, the resulting power can be described in two terms - the KVA or the apparent power and KW or real power. Since the current lags the required voltage of the reactive load, the total resulting power is not the direct summation of the two, but their vector summation. The real power or the horsepower, which is produced by the engine is essentially equal.

Unlike resistive testing, a proper combination of reactive and resistive testing will create conditions in the device in question, which will more precisely simulate the condition faced by the device during a real-time power failure. However, reactive loadbank testing solely can verify the actual performance of the voltage regulator of the Genset. The voltage regulator is not fully challenged in a resistive only load banking test.

The inductive loads that are developed during the reactive testing illustrate how a particular given system will deal with the drop of voltage in its regulator. This inductive load has the capacity of verifying whether the voltage regulator of the system IS working properly. However, the reactive load banking test will be able to tell you whether the voltage regulator is NOT functioning properly. If not, the magnetic field of the system collapses, rendering the generator useless right when it is needed the most.

The resistive and reactive testing combination can also bring in to light any additional stress that the Genset is being subjected to - and determine the condition of the switchgear, alte ators, and the other systems - something that resistive only load bank testing fail to do!

The Issue of Continued Testing

A proper reactive - resistive load bank testing of the complete performance of a system with an experienced service provider will help in proper and genuine verification of whether the system will be able to function to an acceptable standard during any emergency. Only after taking a hard look at the performance of a system and rating its performance metrics, and after due assurance that the different components of the system will able to operate in close coordination with each other, thereby producing the required power, can a facility manager be confident that the business is safe from various threats that are posed by the sustained interruption of the designated utility power service.

However, a regiment of power service does not end at this juncture. Like every modern electric system, emergency power generation equipment must be evaluated and taken care of, periodically, and its individual components need to be tested with due diligence. While a reactive load test will determine the ability of the power generating equipment to function correctly under stresses and load requirements of real-time emergency operations, this must be conducted by a trained and qualified technician who will be able to conduct the test properly.