Phase modulation operation of the hottest small hy

2022-09-19
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Phase modulation operation of small hydropower stations

Abstract: whether it operates in parallel with the national power grid or forms its own independent small power grid with the county as the unit, the serious lack of reactive power also exists. Even the county power, which operates in parallel with the national power grid, cannot obtain a large amount of reactive power from the national power grid to make up for its shortcomings, and it must rely on the county power grid itself to try to solve it. In this regard, the way to solve the reactive power shortage of electrolysis in many counties is only limited to the way of setting shunt capacitors for reactive power compensation. However, it is neglected to use the water turbine generator set of the hydropower station for phase modulation operation, which can also transmit reactive power to the electricity to make up for the reactive power shortage of the county electricity

key words: Untitled Document on the phase modulation operation of hydro turbine generator units in hydropower stations. Counties that mainly supply power by small hydropower, whether they operate in parallel with the national power grid or form their own independent small power grid based on the county, also have a serious lack of reactive power. Even the county power, which operates in parallel with the national power grid, cannot obtain a large amount of reactive power from the national power grid to make up for its shortcomings, and it must rely on the county power grid itself to try to solve it. In this regard, the way to solve the reactive power shortage of electrolysis in many counties is only limited to the way of setting shunt capacitors for reactive power compensation. Ignoring the use of hydro turbine generator units of hydropower stations for phase modulation operation, you can also transmit electricity. After the review of Jinan test King Kong, you can share with those who need it: transmit reactive power to make up for the lack of reactive power in the county power. 1. There are two ways of phase modulation operation of hydropower station (1) the water turbine generator units are not separated. It is very convenient and easy to operate, maintain and manage the undivided water turbine generator set for phase modulation operation. First, open the guide vane of the hydraulic turbine to make the starting speed of the unit gradually reach the rated value. According to the paralleling steps and operation methods when the generator is running, connect the unit to the electric operation. Then gradually turn down the guide vane of the hydraulic turbine until it is fully closed, and stop supplying water to the hydraulic turbine. Adjust the excitation current of the generator rotor according to the reactive power surplus and shortage of electricity, so that the unit operates in the "over excitation" or "under excitation" state, and the unit will output inductive or capacitive reactive power according to the needs of electricity to make up for the lack of electric reactive power. (2) The turbine is separated from the generator. For water turbine generator units that are used for a long time or specially for phase modulation operation, in order to reduce the consumption of active power and the wear of water turbine, the connection between water turbine and generator should be separated, and the generator should be used as a condenser for operation. For the separation of generator and hydraulic turbine, other methods or special prime movers must be used to drive the generator. Therefore, its starting and merging operations are quite different from the non separation status. Using a separate generator for phase modulation operation, the commonly used starting method is the so-called "asynchronous starting", that is, the three-phase power supply is directly added to the three-phase stator winding of the generator that needs to be started, and the generator is started and accelerated with the help of asynchronous torque under the action of power frequency voltage. The moment when the generator starts asynchronously is equivalent to putting an induction motor into the electricity, which will have a great impact on the electricity and greatly reduce the electric voltage. In order to reduce the impact on electricity during phase modulation startup and maintain the electric voltage above a certain value, we must try to limit the starting current of the generator as a phase modulator. Therefore, the step-down starting method adopted when the asynchronous motor is put into operation can be adopted to start the generator. The step-down starting of the condenser is generally to string a group of resistors or reactances with a certain capacity between the condenser and the electricity to reduce the starting voltage. Of course, the autotransformer can also be used to reduce the power supply voltage for the condenser to start. For rural hydropower stations equipped with water resistors to prevent unit runaway, after proper adjustment and wiring of water resistors, water resistors can be used as step-down resistors for the start-up of the condenser. According to the operation experience and the introduction of relevant data, it is better to control the starting voltage of the condenser at 50% - 75% of the rated voltage of the generator according to the actual situation of the electricity and the condenser. When the condenser is put into operation until it reaches the synchronous speed, it first shortens the excitation winding through a resistance about 10 times that of the excitation winding, which is recognized by the automotive industry for excellent enterprises and advanced technology. When starting, it generates an induced voltage in its excitation winding, and the induced voltage value is proportional to its "slip". When the speed reaches the synchronous speed (that is, the slip is zero), the induced voltage is also zero. Therefore, after the condenser is started asynchronously, when the excitation voltmeter on the control panel indicates zero (or close to zero), it means that the speed of the condenser is close to the synchronous speed. At this time, the short-circuit resistance can be disconnected, and the DC excitation current can be input to the rotor winding, so that the condenser can be pulled into synchronization under the action of its synchronous torque. Then continue to adjust the excitation current according to the needs of electricity, and the condenser will send the required reactive power to electricity. 2. As for the county-level power supply mainly supplied by small hydropower for the special condenser, it can be used and added to the plastic masterbatch in the dry season. The redundant units of the hydropower station are changed to phase modulation operation to send reactive power to the electricity. However, in other seasons, in order to generate more active power in the power station to reduce waste water, there is no idle unit for phase modulation operation, which will rapidly increase the electric reactive power shortage, and the reactive power cannot be balanced, resulting in the decline of power supply quality, poor reliability, and increased loss rate. This phenomenon must be overcome. (1) Set special phase modulation unit. In the planning and design of rural hydropower stations, no spare window capacity is considered. The author believes that in order to meet the needs of county power for reactive power, especially in wet seasons, in addition to using economic means to require power users to increase the power factor value of their load operation, it is suggested that rural hydropower stations should set up special phase modulation units with a certain capacity according to their specific conditions, and also serve as the standby capacity of power stations. (2) Installed capacity of dedicated phase modulation unit. For rural hydropower stations close to the load center and at the end of the county power supply, it can be considered to set up special phase modulation units with a capacity of about 50% of the total installed capacity of the power station, so as to supply reactive power to nearby power users, which is extremely beneficial to the loss reduction and energy saving of the county power and the improvement of the operation at the end of the county power supply. Typical examples include tuna and pet food line voltage and the improvement of power supply quality. For the runoff hydropower station, because the station has no regulation capacity, the power station will generate more power

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