Reasons for Unstable Frequency of Diesel Generating Set

If the frequency of the diesel generator set is unstable or deviates from the comparison, it will have an adverse impact on the equipment. The frequency must be kept above and below the rated value 50Hz. Note that the rated power must not be exceeded. When the generator set operates at high frequency, the voltage is high and the frequency increases, which is mainly limited by the strength of rotating machinery. The frequency is high and the motor speed is high. At high speed, the centrifugal force on the rotor increases, which is easy to damage some parts of the rotor. The reduction of frequency will reduce the speed of rotor, reduce the air volume blown by fans at both ends, deteriorate the cooling conditions of generator and increase the temperature of each part.

Next, Dingbo power, the manufacturer of diesel generator set, will explain to you the causes and troubleshooting of frequency instability of diesel generator set.

1. The motor speed used by the user is related to the system frequency. The frequency change will change the motor speed, so it will affect the quality of the product.

2. The frequency instability of diesel generator set will affect the normal operation of electronic equipment.

3. When diesel generating set operates at low frequency, the ventilation capacity of the diesel generator set will be reduced. In order to maintain and ensure the normal voltage, it is required to increase the excitation current to increase the temperature rise of the generator stator and rotor. In order not to exceed the temperature rise limit, the power generation capacity of the generator has to be reduced.

The generating power and frequency of the generator set have a specified range. If it exceeds the range, it will affect the electrical appliances. If the voltage is too high, the electrical appliances will be burned. If the voltage is too low, the electrical appliances will not work normally. The output power is related to the load. For the same load, if the voltage is too high, the greater the current and the greater the power consumption.

4. When the frequency of diesel generator set decreases, the reactive power load will increase, resulting in the decrease of system voltage level.

Next, let's explain the troubleshooting methods for the unstable working frequency of diesel generator set:

A.Bleed the fuel system.

B.Replace the nozzle assembly.

C. Adjust the throttle or clean the oil circuit.

D.The weekly rate converter or weekly rate table fails.

E.Check the electronic governor and speed sensor.

F.Check the shock absorber of the unit.

G.Remove part of the load.

H. Check the fuel filter.

I.Check the fuel pump.

The possible conditions of uncertain faults shall be analyzed and eliminated one by one. For oil circuit problems, if there are oil circuit problems in the diesel generator set system, it will lead to poor oil supply, poor combustion, speed decline and fluctuation. Oil circuit problems include pipeline cracks, air mixed in fuel due to low fuel tank level, filter blockage in oil circuit, oil leakage of fuel pipeline, etc., resulting in discontinuous oil supply of pipeline. According to the inspection, the fuel quality is OK, the filter in the oil circuit is free of dirt and blockage, and the pipeline is well connected. If the speed caused by the fuel injection pump is unstable, the uneven oil supply of each cylinder of diesel generator set will make the speed of the diesel generator set fluctuate.

When the fuel injector fails, during the long-term operation of the diesel generator set, the impurities in the fuel will adhere to the needle valve coupling, causing fuel injection delay and poor atomization, resulting in large and small fuel injection of the fuel injector and unstable operation of the diesel engine. The measurement of speed sensor is distorted. In the control system of diesel generator set, speed is a basic signal for control. This model is equipped with magnetoelectric sensor next to the gear.

If the sensor of the diesel generator set is loose or operates in the dust environment for a long time, it is easy to cause the measurement gap to change, resulting in the distortion of the transmitted data. Moreover, whether the speed regulation control system works well or not directly affects the working performance and even service life of the diesel generator set. If the parameter setting value of the electronic governor in use drifts, it will seriously affect the operating conditions of the diesel generator set, and the parameters of the governor need to be reset.