What Is Parallel Generation?

Electricity is one of the most important energy sources in modern society. A generator is a mechanical device that converts other forms of energy into electrical energy. It is driven by a water turbine, steam turbine, diesel engine or other power machinery. It converts the energy generated by water flow, air flow, fuel combustion or nuclear fission into mechanical energy, and then transmits it to the generator. Converted into electricity by a generator. Generators are widely used in industrial and agricultural production, national defense, technology and daily life.

First of all, the concept of a generator set: A generator set refers to a power generation device that can convert mechanical energy or other renewable energy sources into electrical energy.

In general, our common generator set is usually composed of the following: steam turbine, water turbine or internal combustion engine (gasoline engine,

There are many forms of generators, but their working principles are based on

The generator is usually made up of

Using the principle of electromagnetic induction in which the cutting of magnetic lines of force by a wire induces electric potential, the mechanical energy of the prime mover is converted into electrical energy output. A synchronous generator consists of a stator and a rotor. The stator is an armature that emits power, and the rotor is a magnetic pole. The stator consists of an armature iron core, a three-phase winding that is evenly discharged, and a base and an end cover. The rotor is usually a hidden pole type, consisting of field winding, iron core and shaft, guard ring, center ring and so on. A direct current flows into the rotor's field winding to generate a sinusoidal distributed magnetic field (called a rotor field), and its effective field magnetic flux intersects with the stationary armature winding. When the rotor rotates, the rotor's magnetic field rotates with the same rotation and one revolution, and the magnetic field lines sequentially cut each phase winding of the stator, and three-phase AC potential is induced in the three-phase stator winding. When the generator is running with a symmetrical load, the three-phase armature current is combined to generate a rotating magnetic field with synchronous speed. The stator magnetic field interacts with the rotor magnetic field to generate braking torque. From the steam turbine / water turbine / gas turbine, the input mechanical torque works against the braking torque.

To start a diesel generator set with electricity, the steps are: check whether the electrical contact between the starting motor and the electromagnetic operating mechanism is good. Check that the power cord is correct. Check the battery terminals for dirt or oxidation, and polish them. First check whether the electro-hydraulic specific gravity of the starting battery is in the range of 1.240 ~ 1.280. If the specific gravity is less than 1.180, the battery power is insufficient.

The alternator installation inspection steps are as follows:

When installing the generator, ensure that the cooling air inlet is unobstructed, and avoid exhausted hot air from entering the generator. If there are blinds on the ventilation cover, the windows should face down to meet the requirements of the degree of protection. For mechanical coupling of single-bearing generators, special attention should be paid to the uniform air gap between the stator and rotor.

The alternator is coupled with the diesel generator, and the parallelism and concentricity of the coupling are required to be less than 0.05mm. In actual use, the requirements can be slightly lower, about 0.1mm, too large will affect the normal operation of the bearing, resulting in damage, the coupling must be fixed with a positioning pin. Check the coupling before installation.

The U, V, W, and N marks are printed on the terminals of the generator outlet box, which does not indicate that the actual phase sequence depends on the direction of rotation. UVW printed on the certificate indicates the actual phase sequence when rotating clockwise, and VUW indicates the actual phase sequence when rotating counterclockwise.

When the generator with sliding bearing is coupled, the height of the generator center should be adjusted slightly to the center of your diesel engine, so that the weight of the flywheel on the diesel engine will not be transferred to the generator bearing, otherwise the generator bearing will bear the flywheel The weight is not conducive to the formation of the oil film of the sliding bearing, which causes heat generation and even burns the bearing. Do not carry any heavy objects on the coupling of this type of generator.

If the neutral points of the generators in the power supply system are connected to each other, or when the generator neutral point is connected to the transformer and its load neutral point, the unit will run a neutral current of 3 times the frequency on the neutral line when the unit is running. Therefore, the neutral current of the generator must be measured under various load conditions that may occur during operation. In order to prevent the generator from overheating, the line current must not exceed 50% of the rated current of the generator. The neutral line power is too large, and a neutral line reactor should be installed on the neutral line to limit it.

According to the schematic diagram or wiring diagram, select the appropriate power cable and use copper connectors to connect the copper connector and the bus bar. After the bus bar and the bus bar are firmly fixed, the local gap at the joint is not greater than 0.05mm, and the distance between the conductors is not greater than 10mm, also need to install the necessary grounding wire.

(1) The grounding polarity of the battery must be the same as that of the alternator. Consequences of non-standard use is that the diode is damaged due to the high current discharge of the diode.

(2) When the six diodes of the rectifier are connected to the stator winding, it is absolutely prohibited to use a megohmmeter or 220V AC power source to check the insulation of the alternator. Otherwise, it is easy for the diode to break down and be damaged.

(3) After the engine is turned off, the ignition switch should be turned off. If it is not turned off in time, the battery will continue to discharge, which will affect the magnetic field and shorten the battery life.

(4) When the alternator is running, the fire test method cannot be used to check whether it is generating electricity. Otherwise, it is easy to damage the diode and electronic components.

(5) The grounding form of the regulator and the alternator must be the same, otherwise the alternator will not be able to output voltage because there is no magnetic field current. And the voltage level of the two should be the same, otherwise the charging system cannot work normally.

(6) If it is found that the alternator does not generate electricity or the charging current is small, the fault should be removed in time, and the wire connection between the alternator and the battery should be firm. Otherwise, it is easy to damage the diode and electronic components.

(7) When the alternator is installed on the engine, the center of the pulley groove of the alternator and the center of the pulley groove of the engine must be aligned, and a suitable degree of tightening of the V-belt must be set.

(8) When installing the V-belt early, pry the front cover of the alternator firmly. Otherwise, the component will be crushed ^[1]

Alternator normal maintenance

No-load test machine once a week, running time is 10-15 minutes, in order to detect problems in time and ensure that the battery has sufficient capacity for the generator to start.

1. Before maintenance, the automatic air switch of the generator should be cut off. The main switch should be in the stop position. Fold the positive and negative power cables of the battery to confirm that the generator cannot start.

2. Check the battery electrolyte water level. When it is insufficient, add sulfuric acid solution or distilled water according to its concentration.

3. Calculate the accumulated running time of the generator from the last rearing. The air filter should be cleaned every 50 hours, and the oil filter, diesel filter and water filter should be replaced every 250 hours.

4. Check the unit for water and oil leakage and clean the generator body.

5. Connect the battery power cord and connector, and the test fault indicator should be on.

6. Check if the ground wire is good.

7. Check the operation of the exhaust fan in the engine room, and see if the amount of diesel oil is sufficient for eight hours of operation.

8. Check whether the cold head water level and engine oil level are normal.

9. After the manual test machine runs normally, turn on the automatic air switch of the generator, switch the main switch to the automatic start position, perform a simulated power failure test, and observe the automatic start of the generator.

10. Run the generator for one hour under load, and observe whether the indicators and unit operation are normal.

11. Fill in operation records and maintenance records.

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Alternator Technical Maintenance

Diesel generator sets can be divided into two types according to the use situation: one is based on mains power, the standby power supply of generator sets, and the other is based on generators. There is a big difference between the two types of generator use time. The maintenance of diesel generators is generally determined by the cumulative hours of startup. The first power supply mode described above only tests the machine for a few hours per month, such as the cumulative number of technologies The technical maintenance will be too long after the maintenance hours. Therefore, it should be flexibly mastered according to the specific situation and timely technical maintenance can eliminate the bad phenomenon of the machine as soon as possible, ensure that the unit is in good condition, and extend the service life of the machine. Therefore, in order to make the diesel engine work normally and reliably, the technical maintenance system of the diesel engine must be implemented. The technical maintenance categories are divided into:

First-level maintenance inspection (daily or weekly)

Second and second level maintenance inspection (every 250 hours or one month)

Third and third level maintenance inspection (every 1500 hours or half a year)

Note: 1. Three-level maintenance "," medium maintenance "and" overhaul maintenance "should be completed by a professional diesel generator maintenance company.

2. The standby generator should periodically run the diesel unit for about 10 minutes to evaporate the moisture in the diesel engine body to achieve moisture and corrosion protection.

(I) First-level maintenance inspection

<> Check the oil level

Use a diesel oil dipstick to check the oil level. In order to obtain accurate readings, the oil level should be stopped for 15 minutes, and the oil flow should be checked when it returns to the oil pan. The oil level should be matched with the original oil pan, and the oil level should be kept as close as possible to the high "H" mark.

Warning: Never operate a diesel engine when the oil mark is lower than the low mark L or higher than the high mark H (if necessary, add the same quality and brand oil in the diesel engine).

<> Checking the cooling system

Keep the coolant filled to the working plane, check the coolant plane every day or every time before turning on, analyze the cause of the coolant consumption, and check the coolant plane, only after the cooling system is cooled.

<> Check each connection of the intake pipe

Check the joints of the intake pipe, whether the clamp is loose, whether the hose is cracked, perforated or worn, whether there is any breakage or other damage to the hose, tighten the clamp or replace parts as needed to ensure that the intake system is well sealed and all Air passes through the air filter.

<Four> appearance inspection

Check for leaks of external air, leakage of coolant or oil. Tighten screw connections, joints, etc. or replace gaskets as needed. Check the oil pipe cover of the oil dipstick to see if it is tight.

<Five> check for damage

Inspect the fuel system, including the erroneous investigation or injury of the fuel pump, and inspect all connections for leaks or damage.

<Six> Check the drive belt

Visually inspect the fan, water pump, and charger belt for damage or slack, and replace the damaged buckle with a new one. And adjust the tightness, if necessary, ask a professional technician to adjust.

<Seven> Matters to pay attention to during maintenance

1. Low oil pressure.

2. Insufficient power.

3. The temperature of the coolant or oil is too high.

4. Excessive consumption of coolant, oil and fuel.

5. The engine sound is abnormal, the smoke color is abnormal, and the exhaust pipe is red.

<Eight> matters needing attention when using a dummy load

1. The loading process is 25%, 50%, 75%, 100%.

2. Revise the actual power used.

3. Run for one hour at full load.

4. Observe the various output parameters of the oil machine at all times during the loading process.