What Are The Causes Of Generator Oscillation

1. What is "analog quantity" and "switch quantity"?

Answer: analog quantity -- show unit speed, fixed rotor current, voltage and the temperature of each guide bearing, water pressure, oil pressure and other numerical simulation quantity as well as line, bus voltage, frequency, line current, whether there is power and the main variable temperature and other numerical simulation quantity;

Switching quantity -- shows the split and close of the circuit breaker, knife switch, magnetization switch, active power increase and decrease, and the status of the solenoid valve.

2. What is closed-loop control system?

A: All the output signals of the control system can have a direct influence on the control function of the system are called closed-loop control system. The governor system and the microcomputer excitation and dispatching system belong to the closed loop control system.

3. What are the causes of generator oscillation?

Answer: A. Static stability damage, mainly due to the change of working method or fault point excision time is too long;

B. Sudden increase of impedance in combination of generator and system;

C. Power mutation in the power system causes severe imbalance between supply and demand;

D. Reactive power in the power system is severely insufficient, and voltage drops suddenly;

E. Generator governor malfunction.

4. Why is the generator equipped with an air cooler?

A: Generator at work, but because of the current and magnetic field, will surely happen iron loss and copper loss, the loss in the way of heat to the static winding and iron core so that the temperature rise of winding, drop generator power, on the other hand also makes generator static winding and iron core insulation burn cause fire in the generator  air cooler can make the hot air inside the generator into the cold wind, The heat is carried away by the cooling water.

5. What is the big shaft grounding brush, what is the role of the big shaft grounding brush?

A: The large shaft grounding brush is a carbon brush connected to the main shaft of the generator and its other end is grounded. 

The role of the large shaft grounding brush is:

A: Eliminate the shaft current, the shaft current into the earth;

B: Monitor the insulation of the generator rotor and serve as one-point grounding and two-point grounding protection for the rotor. When a large current flows through the grounding brush, it can be judged as insulation damage and grounding;

C: Measure positive and negative voltage to ground of generator rotor.

6. What is the danger of shaft current?

Answer: Due to the existence of the shaft current, there is a small arc corrosion between the journal and the bearing bush, which makes the bearing alloy gradually stick to the journal, damages the outstanding working surface of the bearing bush, causes the overheating of the bearing, and even melts the bearing alloy. Because of the long-term electrolysis of the shaft current, the lubricating oil will also degenerate and blacken, reducing the lubrication function and increasing the bearing temperature.

7. What kinds of main valves are there? What is the function of butterfly valve?

Answer: the main valve is divided into: ball valve, used for more than 200 meters of water head; Butterfly valve, water head above 200 meters. Widely used and gate valve butterfly valve role:

A: As backup protection of unit overspeed;

B: reduce water leakage when the guide vanes of the unit are fully closed;

C: convenient for maintenance, when one maintenance or fault closing its main valve does not affect the normal work of other units;

D: For power stations with long water diversion pipes, only the main valve can be closed instead of the dam entrance gate when the unit is shut down or repaired, so that the water diversion pipes can be in the waiting state of filling water and the waiting time of filling water can be saved;

E: Butterfly valve can only open in still water, but can be closed in moving water;

F: Butterfly valve is only fully open and fully closed two conditions, is used to block the flow of water, but can not be used to adjust the flow.

Guangxi Dingbo Power Equipment Manufacturing Co., Ltd. established in 2006, is an manufacturer of diesel generator in China, which integrates design, supply, commissioning and maintenance of diesel generator set. Product covers Cummins, Perkins, Volvo, Yuchai, Shangchai, Deutz, Ricardo, MTU, Weichai etc. with power range 20kw-3000kw, and become their OEM factory and technology center.