Why Should A Dummy Load Test For Diesel Generators Be Performed Regularly?
In today's world, commercial businesses rely on emergency power systems as backup power during power outages, and backup power equipment must be able to operate seamlessly during grid outages and startups. If power failures are not mitigated, this can have a dramatic impact on the normal operations and production of a business - from operational disruption to inevitable financial losses.
Consider a large grid that supplies power to all end users in residential, commercial, enterprise or industrial applications. While the size of the affected area may be small, sudden or planned outages can have a knock-on effect, causing power difficulties in nearly all industries. For example, in the event of a power outage, hospitals need to rely on backup power systems to store related medicines and mechanical ventilators to keep patients alive. As a life-or-death precaution, it is critical to address backup power issues early in the planning phase.
For businesses with emergency diesel generator systems that start automatically in the event of a power outage, the question here is: are they automatic and functioning properly? If yes, are they running at maximum capacity? This is why a dummy load test should be performed to determine if a diesel generator set can operate at peak performance. The periodic frequency of load bank testing (annual, semi-annual, quarterly or monthly) will depend on operational requirements, load application, power, capacity, rating and the type of generator set itself.What is a diesel generator dummy load test?
Diesel generator set load testing is an important aspect of preventive maintenance and requires a thorough evaluation and inspection of generator components under load. Backup and emergency power systems operate with little or no load for extended periods of time without frequent power outages in the area. However, this is not enough as there is no guarantee that the generator will reach its full performance in the event of a power outage. Over time, generators can become insensitive - if not maintained, at worst - potentially leading to fire and safety hazards, high operating costs and increased emissions.
Diesel generator set load test is used as a guarantee for emergency selection in the case of emergency power supply. Although generators are often exposed to light loads, periodic testing is required to ensure they meet some of the strictest electrical codes. To eliminate unnecessary downtime and ensure continuity of current, generators should be dummy load tested.
In fact, standby and emergency diesel generator systems require acceptance testing upon initial installation. According to relevant regulations, during the initial commissioning, the backup and emergency diesel generator systems should be tested at full load on site. In addition to initial acceptance testing, monthly load library testing is required. Some particularly important industries need to take further proactive precautions with quarterly, semi-annual and annual load testing of generators.
Here's a general rule of thumb: When a generator does not exceed 30% of its rated power load, a dummy load test needs to be considered. The minimum load on the generator should be 30% of the rated power, or the manufacturer's recommended appropriate exhaust temperature. Otherwise, ignoring regular maintenance or running the generator at zero to light loads can have ill effects.
For example, diesel generators that do not reach 30% of their kW rating are prone to carbon deposits. Diesel generators can only be run on a light load or zero frequency basis, and over time certain components of diesel generators (such as injectors, exhaust valves and exhaust systems) can accumulate carbon that can lead to unburned of fuel, dirt buildup, oil spills and black combustion gases.
To correct the situation and burn off the carbon deposits, start the diesel generator for a dummy load test and run the engine at 30-40% rated load for a few hours depending on the situation. Running a diesel generator at full power will recalibrate it to its nominal operating temperature and pressure level, which obviously helps with the purpose of periodic dummy load testing.
How Generator Load Bank Tests Work
The daily operation of electrical equipment is critical to its proper maintenance and efficient operating condition. To test that the generator is in working condition, run it at maximum operating capacity for a period of time under load.
The generator is tested at full kW output rating with a dummy load in incremental steps to verify that it can produce the required maximum horsepower when connected to the generator AC output. This load step switching can be calibrated through the control panel to properly match the rated capacity of the generator. Critical data such as engine parameters (appropriate operating temperature and pressure levels) are simultaneously recorded to measure the efficiency of the generator each time the kilowatt load is added. In addition to dummy load testing, as a precautionary measure, infrared scanning can be used to detect problems early.
Specifying a dummy load requires consideration of physical configuration and installation considerations. Dummy loads can be permanent or temporary and can be used for a variety of purposes - unit mounts, radiator mounts or portable. When installing a dummy load, location is the main consideration. For permanent load bank installations, minimal physical separation between the load bank, building, and landscape is required for proper cooling airflow and damage control.
As demand for reliable emergency power systems surged, so did diesel generator load banks. Periodic dummy load bank testing of diesel generators to ensure diesel engine backup capability, proactively identify problems, optimize cooling system performance and eliminate carbon deposits.
