Aux 2 Unit 7 Q4

Let’s describe the operation of a diesel generator speed and load sensing electronic governor:

Purpose

• The primary function of an electronic governor is to maintain a stable engine speed (and thus generator frequency) under varying load conditions.
• It achieves this by adjusting the fuel supply to the engine in response to changes in speed and load.

Key Components and Functions:

1. Electronic Control Unit (ECU):
   • The “brain” of the system, it receives input signals from various sensors and processes them to determine the required fuel adjustment.
   • It sends control signals to the actuator to modify fuel injection.
2. Speed Sensor:
   • Measures the engine’s rotational speed, usually by sensing the frequency of the generator’s output voltage or using a magnetic pickup on the engine.
   • Provides feedback to the ECU about the actual speed.
3. Load Sensor:
   • Measures the electrical load on the generator.
   • Provides feedback to the ECU about the power demand.
4. Actuator:
   • A device (often a solenoid or stepper motor) that physically adjusts the fuel rack or control lever on the engine’s fuel injection pump, thereby controlling the amount of fuel injected.
   • Receives control signals from the ECU.

Operational Sequence:

1. Steady State:

• The engine runs at the desired speed, and the generator supplies the required load.
• The speed sensor and load sensor provide continuous feedback to the ECU.
• The ECU compares the actual speed and load to the set points and maintains the actuator position accordingly.

2. Load Increase:

• The load sensor detects an increase in electrical demand.
• The ECU receives this signal and anticipates a potential speed drop due to the increased load.
• It sends a control signal to the actuator to increase fuel injection.
• This additional fuel compensates for the increased load, preventing a significant speed drop and maintaining the desired frequency.

3. Load Decrease:

• The load sensor detects a decrease in electrical demand.
• The ECU anticipates a potential speed increase due to the reduced load.
• It sends a control signal to the actuator to decrease fuel injection.
• This reduction in fuel prevents the engine from overspeeding and maintains the desired frequency.

4. Speed Deviation:

• Even without load changes, the speed sensor might detect minor speed deviations due to factors like fuel quality or engine wear.
• The ECU continuously monitors these deviations and makes small adjustments to the fuel injection to keep the speed within the desired range.

Advantages of Electronic Governors:

• Precise Control: They offer accurate and responsive control of engine speed and frequency.
• Load Sharing: In multi-generator systems, they enable efficient load sharing between generators.
• Adaptability: They can be programmed with various control algorithms and parameters to suit different engine and application requirements.
• Diagnostics and Monitoring: They often include built-in diagnostics and monitoring capabilities for troubleshooting and performance analysis.

In summary, a diesel generator speed and load sensing electronic governor uses sensor feedback and electronic control to precisely regulate the engine’s fuel injection, maintaining stable speed and frequency under varying load conditions. It’s a crucial component for ensuring reliable power generation and efficient operation of the generator system.