Power outages can be detrimental, in varying degrees of severity, to any facility. Businesses need to implement measures to reduce or eliminate the negative consequences of power interruptions. This is particularly important where the utility is unreliable and struggles to provide continuity of supply. Popular power continuation solutions usually include the choice between a generator or an uninterrupted power supply (UPS).
A UPS is a device that allows electrically operated equipment to continue operating normally when the main incoming electrical source is interrupted. The uninterrupted power supply most encountered will be the UPS that keeps your computer running for a short period of time while you save your work and shut it down after the incoming power fails. While grid is available, the batteries in these units are kept charged or are recharged after outages. The duration for which an uninterrupted power supply can provide electricity to its intended load is referred to as grid autonomy. All uninterrupted power supplies rely on some form of stored energy that can be converted into electricity when the grid fails. Batteries are the most common energy storage method used in a UPS, but energy can be stored in many ways. Even conventional diesel and petrol generators can be considered a form of uninterrupted power supply depending on how they are configured and used.
Dynamic uninterrupted power supply systems are typically used for commercial and industrial operations that have critical or sensitive electrical equipment that must be kept running continuously. Server farms, data centres, and medical facilities are common examples of facilities that would use dynamic uninterrupted power supply systems. These systems are composed of a large, constantly rotating flywheel, an alternator which can also serve as an electric motor, control electronics, and a diesel engine. When the grid is present, electricity from the grid powers the alternator, which acts as an electric motor and rotates the flywheel. The mass of the rotating flywheel stores a substantial amount of rotational kinetic energy. This energy energises the loads when the grid fails allowing time for the diesel engine to be started, after which the alternator is switched from motor to alternator mode and the system then acts as a conventional diesel generator.
A generator is an electromechanical device that converts rotational kinetic energy into electrical power in accordance with Faraday’s laws of electromagnetic induction. Three phase, diesel, petrol or natural gas-powered generators, convert some of the chemical energy – stored in these fuels – into mechanical energy through combustion. An internal combustion engine (powered with diesel or petrol) is used to rotate an armature made up of copper coils wound around a metal core inside a magnetic field. This is made by a series of magnets to produce electricity. Although generators are typically diesel powered there is no reason why hydro power, petrol, wind, or steam could not be the source providing the rotational energy required. A generator is often referred to as a genset because it consists of two primary components, the engine and an alternator or generator end. The combination of a diesel engine, alternator and ancillary devices is also referred to as a ‘diesel generator set’ or shortened to a ‘genset’. Ancillary devices that might form part of a genset include control systems, jacket water heaters and circuit breakers. An array of programmable logic controllers, for gensets, are also available that provide a wide range of functionality, including remote monitoring of the genset and remote run and switch off.
Deciding between a UPS and a generator can be difficult. In broad terms, a genset offers a backup power source, while a UPS protects critical appliances and electronics against power surges and short duration grid interruptions. There are several differences between the two and in some instances, it may be beneficial to consider both to ensure full protection against power interruptions and poor grid power quality.
Diesel gensets work independently of the grid and can therefore function without being connected to a power grid at all. When properly maintained and supplied with fuel, they can run continuously or for very long periods This characteristic makes them suitable for primary power, where there is no grid, or for standby or emergency power in the event of a grid failure. Gensets provide a long duration backup power supply and can generally sustain business activities for much longer than a UPS will be able to. A generator is an extremely flexible power solution. Gensets are available in a vast range of sizes and several different fuel types. They can be configured to produce electricity in single or three phase alternating current (AC) or to produce direct current (DC) output.
The primary limitation of a generator is the time it takes to take over from the grid when it fails. Even the best gensets, with automatic mains failure (AMF) start-up, will take up to a minute to start and ramp up to full power. This will be substantially longer with manual change over arrangements. This makes a generator unsuitable for critical or sensitive loads which need instantaneous, clean, uninterrupted power. The more secondary draw backs of gensets include noise and exhaust emissions.
A UPS offers automatic, instant battery backup which continuously protects critical IT systems, medical equipment, and sensitive electronic equipment from being interrupted, and potentially damaged, by unexpected power outages, power quality issues and grid failures. A UPS eliminates the dangers that ‘hard shutdowns’ expose certain electronic equipment to. UPS systems produce zero carbon emissions making them environmentally friendly. A UPS requires no maintenance, while gensets will always require some maintenance.
The primary limitation of a UPS is that typically provides back up power for a relatively short duration. Usually to provide time for sensitive devices and computer equipment to be powered down in a controlled manner or to bridge any gap between grid failure and the genset starting up.
A UPS and genset working in tandem is often the gold standard for power protection providing the best of both technologies to ensure continuous and perfect power to your equipment. PacB are industry leaders in the provision of diesel gensets, but we also offer renewable energy solutions and uninterrupted power supply systems. If you need a continuous power supply system of any type, talk to PacB. We can assist with units from as small as 1 kVA through to and including utility scale devices. We can design and engineer tandem generator and UPS systems to suit any requirement. Contact PacB today for anything related to power supply systems, whether genset, UPS or renewable energy.
Our qualified technicians offer support and advice in the selection of the right power solution for your needs by calculating your power requirements.