Diesel generators, gas engines and steam turbines often require a governor to maintain a set speed under varying load conditions. This is a critical aspect of power generation and backup power.
Generators can have mechanical control or electronic control governors. Mechanical controls are used in older generators and advanced electronic control is found on newer generators.
Power Generation
Electric generators need to run at a specific speed (or frequency) to produce clean power. The governor on a generator is responsible for regulating the generator’s speed to match the system’s frequency.
For example, if a generator is running faster than its nameplate capacity, it’s likely to start burning more fuel to keep the engine going. The governor on the generator will sense this and reduce the amount of fuel delivered to the engine.
This control is also necessary to prevent the generator from running at an excessive rate and damaging itself or other components. This type of governor can be actuated hydraulically or electrically.
Unlike the nameplate prime rating of a generator, its operating capability (derate rating) is determined by a variety of factors including ambient temperature, altitude, and fuel quality. This means that the system must be able to share a generator’s operating capacity with other generators without exceeding its nameplate rating.
Backup Power
In commercial and institutional applications, backup generators provide a critical source of power in the event of an electrical outage or loss of mains supply. These systems automatically monitor the incoming power supply and start a generator to keep essential equipment running, such as air conditioning and communications, until mains supplies are restored.
The key to preventing problems during this transition is proper generator sizing. This is crucial for ensuring the UPS system holds voltage and frequency within acceptable input tolerances during the reconnection process.
Generators are sized according to their ‘Running Watts’ (watts/hours continuously produced) and ‘Surge Watts’ or ‘Max Watts’ (watts/hours surged to start electric motors) ratings. While ‘Running Watts’ are more conservative than ‘Surge Watts’, they may not be enough to prevent a generator from over-heating or overloading when used for short durations and high demands.
To protect against erratic load surges, generators with mechanical or electronic governors must be installed. These control devices use sensors and actuators to measure the engine speed and regulate fuel supply accordingly. They can be controlled in constant-speed mode or droop speed mode, depending on the generator’s needs.
Off-Grid Power
Off-grid power systems rely on alternative energy sources, such as solar or wind. These renewable energy sources don’t use fossil fuels, which reduces your carbon footprint and lowers your energy costs.
Many off-grid power systems also include battery storage. This lets you store electricity you generate for use at a later time, or to charge your equipment when the sun isn’t shining.
A gas generator governor is used to control a generator’s speed. It is also used to regulate the output voltage from a generator.
The governor is controlled by a computer, which monitors voltage from the electrical system (grid). It then uses algorithms to determine the best setting for the generator.
This optimization problem is complex because it combines technical and security constraints from the utility grid with each generator’s set point. This is why it is necessary to have a smart power system with multiple microinverters and batteries.
Commercial Applications
A gas generator governor is a device used to control the speed of a generator driven by a diesel or gas engine. This device can be either mechanical or electronic.
A mechanical governor is the simplest and cheapest type of unit fitted to a diesel engine. It works by using springs to try to maintain the engine’s speed at a fixed level.
An electronic generator governor, on the other hand, uses a stepper motor to move in whole steps to keep the engine’s RPM at an optimal level. The stepper is controlled by a proportional-integral-differential (PID) control system that compares the generator’s RPM with a preset set point.
The generator’s PID controller then calculates the results and sends an output to an actuator that implements the governor’s corrections on the fuel supply to the engine. The result is a stable, optimized fuel supply that meets the power requirement of the application. The system is also flexible enough to change the configuration for different applications.
