Summary Of Advantages And Disadvantages Of Parallel Operation Of Diesel Generator Sets

Summary of Advantages and Disadvantages of Parallel Operation of Diesel Generator Sets

 

I. Core Advantages

1. Flexible Power Supply Expansion
The power of a single unit is limited, but multiple units in parallel can stack power to meet high load demands. Additional units can be added later if the load increases, without the need to install an excessively large single unit at once.

 

2. Significantly Enhanced Power Supply Reliability
When one unit fails or undergoes maintenance, the remaining units can automatically carry the load, preventing a total power outage. This is suitable for hospitals, data centers, factories, base stations, and other critical loads.

 

3. More Reasonable Load Distribution and Fuel Efficiency
The parallel system automatically shares active and reactive power. During light loads, only a few units operate, avoiding low-load inefficient operation of a single unit, reducing overall fuel consumption and carbon deposition wear.

 

4. Maintenance Without Power Interruption
Units can be serviced or repaired in rotation without cutting off power, achieving uninterrupted emergency power supply and suitable for scenarios where continuous power is required year-round.

 

5. Strong Redundancy for Backup
Multiple units in parallel serve as backups for each other, eliminating the need for a single oversized standby unit, making redundancy configuration more economical.

 

6. Minimal Startup Impact
Multiple units can be connected to the grid in steps to share the load, avoiding the current surge caused by a single unit taking a large load at once, thus protecting both the units and the load equipment.

 

II. Main Drawbacks

1. Higher Initial Investment
Additional equipment like parallel control cabinets, synchronizing modules, bus tie cabinets, parallel busbars, and protection devices are needed, making the equipment and installation costs much higher than for a single unit.

 

2. Complex Control and Maintenance
You need to handle frequency and voltage synchronization, load sharing, and protection interlocks, which require skilled maintenance personnel; commissioning and parameter tuning are tedious.

 

3. Fault Risks Are Linked
If the parallel system fails to synchronize, has excessive circulating current, or protection fails, multiple units may trip simultaneously, and generators could even be damaged.

 

4. Circulating Current Losses Exist
Small differences in voltage, phase, or frequency between units can generate internal circulating currents, causing losses and heating, and in severe cases, winding burnout.

 

5. Higher Space and Room Requirements
Multiple units plus parallel distribution cabinets and bus trunking take up more space, and costs for room ventilation, smoke exhaust, noise reduction, and foundation work increase.

 

6. Low Loads Can Be Uneconomical
At very low loads, if the parallel logic is not set properly, multiple units may run lightly loaded, leading to carbon buildup and higher fuel consumption.

 

Ⅲ. Recommended Applicable Scenarios

- Suitable for: High-power loads, situations where power cannot be interrupted, requiring redundant backup, and construction sites/factories/data centers/hospitals/shopping malls that may expand later.

- Not suitable for: Low-power loads, fixed loads, scenarios with limited budgets, or simple backup situations without professional maintenance personnel, where a single unit is more cost-effective.