The Dangers of Parallel Loading Two Un-Synchronized Generators

Parallel loading or connecting multiple generators to a common electrical system without proper synchronization can result in severe damage to the equipment and potential safety hazards. This article explores the risks associated with un-synchronized generators and the necessary steps to ensure a safe and effective connection.

Introduction to Parallel Generators

Parallel generators are used to provide an additional source of power in commercial, industrial, and residential settings. By connecting these generators in parallel, the electrical systems can be augmented to handle higher loads and ensure a more reliable and consistent power supply. However, proper synchronization is crucial before connecting the generators to prevent damage and maintain system integrity.

The Risks Involved

One of the most significant risks of parallel loading un-synchronized generators is the potential for very high current flows and, consequently, the tripping of generator breakers. This situation can be akin to a short circuit, depending on the phase difference between the generators. The fault currents can be exceptionally high, which can result in severe damage to the generators, whether they are loaded or not.

Another risk is the visibility of fast transients in the connected loads. Depending on the state of the generator breakers, these transient events can cause a sudden loss of power. In some cases, both generator breakers might trip simultaneously due to the similar power flows.

Implications of Different Terminal Voltages

When the terminal voltages of the two generators are different, circulating currents will flow between them. The impedance of the generators is very small, leading to extremely large circulating currents. This can cause severe damage to the generators and disrupt the entire electrical system.

Necessary Precautions and Solutions

To avoid these risks, it is essential to use an automatic synchronizer and a voltage regulator before connecting the generators in parallel. The automatic synchronizer ensures that the phase angle, frequency, and voltage of the generators are identical before they are connected. The voltage regulator then shares the reactive power, ensuring that no single generator becomes overloaded.

Proper grounding is also critical. The earth of the generators should be connected to a common grounding point, and the neutral and hot wires should be connected together. This ensures a stable voltage output and reliable protection against overvoltage.

During fault conditions, the voltage regulator enhances the system’s excitation to ensure that maximum synchronizing power is available during fault clearance. This further reduces the risk of equipment damage and ensures the stability of the electrical system.

Conclusion and Importance of Proper Procedures

Parallel loading two un-synchronized generators is not only ineffective but also extremely dangerous. It is imperative to follow the proper procedures and use the necessary equipment, such as automatic synchronizers and voltage regulators, to ensure a safe and reliable connection. Ignoring these precautions can result in significant damage to the equipment and potential safety hazards. Therefore, it is crucial to prioritize the synchronization of generators before attempting to connect them in parallel.

Frequently Asked Questions

Q: Why is it important to synchronize generators before connecting them in parallel?

A: Synchronizing generators before connecting them ensures that the phase angle, frequency, and voltage are consistent, preventing high current flows and severe damage.

Q: What is the role of a voltage regulator in parallel generator systems?

A: A voltage regulator helps to share the reactive power, ensuring that no single generator becomes overloaded, and maintains stable voltage output.

Q: What happens if generators are not synchronized and a fault occurs?

A: Fault conditions can result in very high fault currents, leading to damage to the generators and potential loss of power to connected loads.

In conclusion, ensuring the proper synchronization and use of necessary equipment is critical for the safe and effective parallel operation of generators. Neglecting these procedures can result in significant risks and damages. For further information and assistance, please consult with a qualified electrical engineer or refer to relevant industry standards.