What are the consequences of generators not being tied at the same time?

If the size, frequency and phase are different, there is asymmetry in the parallel, and the magnitude and direction of the instantaneous voltage are inconsistent, resulting in the "collision" when paralleling, which will cause the generator to be impacted by the external force of the power grid, and the generator will also have an impact on the power grid.

A large impulse current is generated, which will cause the deformation and damage of the generator rotor in serious cases, and even cause the power grid to oscillate and disconnect the power system. Therefore, the parallel of generators must not be sloppy.

Assuming that the generators are not parallel at the same time, first of all, the voltage, active power and current of the generator fluctuate greatly, which can swing in full amplitude, and at the same time, the impact on the generator is very large when it is paralleled, and the generator makes a "coaxing" sound, and the generator vibrates beyond the normal value.

At this time, the motor outlet switch and excitation switch should be disconnected. Dismantle the generator and check the damage to the generator, especially the rotor and base. Then judge whether to put it into use according to the situation.

A generator is a mechanical device that converts other forms of energy into electrical energy, which is driven by a water turbine, steam turbine, diesel engine or other power machinery, and converts the energy generated by water flow, air flow, fuel combustion or nuclear fission into mechanical energy and transmits it to the generator, which then converts it into electrical energy. Generators have a wide range of uses in industrial and agricultural production, national defense, science and technology, and daily life.

Non-synchronous parallels of generators are generally protected from jumping. If there is no corresponding protection, then the generator will run asynchronously, and the rotor will generate a higher induced voltage, which may even threaten the rotor and destroy the rotor insulation.

If large generators are not in parallel at the same time, the stability of the power grid may be affected.

Of course, the non-contemporaneous period mentioned here refers to those that are not within the scope permitted by the equipment or national standard.

In normal parallelism, it is not possible for the generator to be completely synchronous, and it is acceptable in a small range. When the difference is large and exceeds the allowable value, it will have a relatively bad effect, which is what we usually call non-contemporaneous.

Unless the breaking capacity of the air switch of your unit is much greater than the bearing capacity of the generator, or the air switch is damaged, otherwise the huge impulse current of the non-synchronous parallel will be put.

The excitation system of the generator is burned instantaneously (such as the rectifier tube), extended to the stator coil burned, and even causes the power grid to oscillate so that the power system is all disconnected, so the generator parallel can not be sloppy, this situation can only occur when the manual parallel is in place, and now the automatic parallel system is impossible to happen.

The conditions for generators to be tied at the same time are:

1) The generator voltage is equal to the system voltage, and the allowable voltage difference is not more than 5%;

2) The generator frequency is equal to the system frequency, and the allowable frequency difference is not greater than;

3) The phase of the generator voltage is the same as the phase of the system voltage;

4) The phase sequence of the generator voltage and the phase sequence of the system voltage are the same, and the waveform is the same.

Non-contemporaneous juxtaposition is a serious accident of the power plant, which has great destructive force on the relevant equipment such as the generator and its series of virtual transformers, switches, etc., and in serious cases, the generator coil will be burned and the end will be deformed, even if the equipment is not immediately damaged at that time, it may cause serious hidden dangers.

As far as the entire power system is concerned, if a large unit is not in parallel at the same time, it will have a great impact, which may cause power oscillation between the generator and the system, seriously disrupt the normal operation of the whole system, and even cause a collapse.

The generator is completed in parallel at the moment of the same period, and the moment of grid connection has nothing to do with active and reactive power, which is just a conventional operation method to prevent the occurrence of non-synchronous parallel danger.

There are two methods of parallel synchronization of Fa Qing Sui motor: quasi-synchronous and self-contemporaneous. Quasi-simultaneous is accurate synchronous, which is generally carried out by manual operation. Self-synchronization is an automatic control operating device.

Three conditions should be met for both juxtaposition methods:

1. The voltage of the generator to be merged is equal to the voltage leakage difference of the system;

2. The weekly rate of the generator to be merged is equal to the weekly rate of the system;

3. The phase angle of the generator to be merged is consistent with the phase angle of the system.

The conditions for generators to be tied at the same time are:

1. The generator voltage is equal to the system voltage, and the allowable voltage difference is not more than 5%;

2. The generator frequency is equal to the system frequency, and the allowable frequency difference is greater than Hertz;

3. The phase of the generator voltage and the phase of the system voltage are the same;

4. The phase sequence of the generator voltage is the same as that of the system voltage, and the waveform is the same.

Non-contemporaneous juxtaposition is a serious accident in the power plant, which has a great destructive force on the relevant equipment such as the generator and its series transformer, switch, etc., and in serious cases, the generator coil will be burned and the end will be deformed, even if the equipment is not damaged immediately, it may cause serious hidden dangers.

As far as the entire power system is concerned, if a large unit is not in parallel at the same time, it will have a great impact, which may cause power oscillation between the generator and the system, seriously disrupt the normal operation of the whole system, and even cause collapse.

Non-contemporaneous juxtaposition will produce a lot of self.

The impulse current and impulse torque, the generator and the equipment connected to the generator will bear the electric power and heat generated under the action of DAO20 30 times the rated current, which will cause the generator stator coil to deform, twist, insulation cracking, coil joint melting, etc., in serious cases, resulting in damage and burning, end deformation.

If a large unit is not parallel at the same time, power oscillation will occur between the unit and the system, which will seriously disrupt the normal operation of the whole system and even cause the stability of the power system to be damaged.

In order to prevent non-contemporaneous accidents, the following measures should be taken:1Parallel personnel should be familiar with the primary system and the secondary system.

2.Strictly enforce the rules and regulations, and strictly implement the operation ticket system. 3.

Technical measures should be taken to prevent non-simultaneous parallels, such as the use of synchronous mortising, simultaneous angle locking, automatic quasi-simultaneous parallel devices, etc. 4.Before a newly installed or overhauled generator is put into operation, it is important to check the phase sequence of the generator system and perform a nuclear phase.

The secondary circuit of the relevant voltage transformer should also be nuclear after overhaul.

Non-contemporaneous juxtaposition of generators

It is very harmful to the generator and the main transformer, circuit breaker and other electrical internal equipment connected in series, and when the capacity is serious, it will burn the generator winding and deform the end. If such an accident occurs in a large generator, there will be power oscillations between the machine and the system, affecting the stable operation of the system.

"Since the excitation voltage is DC and there is no phase, what is the phase of the established terminal voltage and potential", the phase of the terminal voltage is determined by the position of the generator rotor, and has nothing to do with the excitation current.

You still don't understand the principle of self-synchronicity. First of all, self-contemporaneous is only suitable for salient pole generators. Since the same period after closing, when there is no excitation, the generator is equivalent to a motor, and the stator magnetic field acts on the salient rotor, and the convex pole of the rotor will be attracted by the stator magnetic field, and the convext pole will naturally align with the magnetic pole of the stator magnetic field, so that the rotor is pulled into synchronization by the stator magnetic field, and then the excitation is added, and the established terminal electric potential is naturally in the same phase as the system.

Since the same period, it is actually to close first, and then add excitation at the same time.

The parallel of generators means that the voltage, phase and frequency before the generator is closed are the same as the grid, so what if? If there exists, it cannot be called the same period.

There are two ways to parallel:

Method 1 (now commonly used): the unit starts, excites, the generator reaches the rated voltage and meets the synchronization conditions, and the machine is paralleled;

Method 2 (commonly used in Europe before): drag and parallel, start in the unit, do not give excitation, after the engine reaches the rated speed, give excitation, parallel within 30V, drag each other.

What if there is a lot of phase difference with the system side? Since the simultaneous closing, there is a process of dragging into the synchronization.