Load Bank Testing – What It Is and How It Works

An Uninterruptable Power Supply (UPS) usually sits in between the protected loads and an alternative power source such as a diesel generator. The way a UPS is designed, it continuously powers connected loads through their inverter. The same inverter also allows conditioning of the mains supply voltage and in the event of a mains failure, it ensures a break free supply of electric energy.

In many applications, the utility of a UPS is indispensable. Without this piece of equipment, business continuity can be hampered during a temporal power outage. Because of the value your business can derive from a UPS system, it is important to implement load bank testing so that you can be sure the system meets your requirements.

What is Load Bank Testing?

Load bank testing is simply a validation of the battery autonomy and correct operational performance of the UPS system. Generally, load bank testing, assesses the generator and UPS under load conditions. This exercise is mostly carried out as part of preventive maintenance.

The strength of a UPS battery set depends on the strength of its weakest battery cell. Through load bank testing, you can also ascertain the condition of UPS batteries as well as strings. These indicate whether or not individual cells are coming to the end of their useful life. This gives you an early warning and good timing for replacement. Suppliers of power protection equipment offer load bank testing as a service. Some of them may offer the testing as a package of the UPS commissioning process.

It’s important that the load bank testing is not done at least in the first week after the commissioning process of the UPS. This is because during this time, the voltage is equalizing across the battery blocks and the batteries may not as yet be fully charged. If the testing is done during this time, the results yielded may not be accurate.

Why Do Load Bank Testing?

The whole point of doing a load bank testing is to validate the power protection system under different load conditions without risking power supply to the protected load. Insofar as people invest in UPS systems, their hope is that they will not use them at any point in their operations. However, instead of waiting until the fault occurs for you to know the performance of your UPS, you can do simulations known as load bank testing.

It is not just important to know that your generator will start automatically following a power failure, but whether it will actually run and serve you.

How Load Testing is Done

Load banks should have suitably rated cables that enable them to be placed at a distance not more than 20 meters from the output power distribution unit or UPS terminals. The load banks consist of heating elements and fans. During the test, allowances should be made for noise attenuation and heat dispassion.

The measurements taken during discharge help in determining system and battery performance. Through a load bank test, you can determine beforehand any problems your UPS and generator may have and the corrective measures to be undertaken.