1. Manual frequency modulation: In this method, the operator manually adjusts the output of the generator set according to the real-time change of the system frequency to maintain the stability of the system frequency.
Advantages: mature technology and easy implementation.
Disadvantages: depending on the operator's experience and reaction speed, improper operation may lead to excessive frequency fluctuation. In large power systems, artificial frequency modulation may not meet the real-time requirements.
2. Automatic frequency modulation: This is a method to realize secondary frequency modulation through automatic control system. The automatic control system can automatically adjust the output of the generator set according to the system frequency monitored in real time.
Advantages: fast response and real-time tracking of system frequency changes.
It does not depend on the operator's experience and reaction speed, and can better maintain the stability of the system frequency.
Disadvantages: It needs complicated automatic control system and is difficult to realize.
If the automatic control system fails, it may affect the effect of secondary frequency modulation.
3. Compared with the primary frequency modulation, the secondary frequency modulation has a wider adjustment range, and it can realize the lossless adjustment, but the adjustment time is longer. In practical application, secondary frequency modulation is mainly used to compensate the deficiency of primary frequency modulation and further improve the stability of power system.
The main purpose of realizing secondary frequency modulation in power system is to maintain the stable operation of power system;
In power system, primary frequency modulation is mainly to adjust the speed and power of generator to respond to the change of load. However, the adjustment range of primary frequency modulation is limited and the adjustment speed is slow, which can not meet the real-time and accurate adjustment requirements of power system.
The secondary frequency modulation is based on the primary frequency modulation, and the output power of the generator set is adjusted more finely through the automatic control system. Secondary frequency modulation can quickly respond to the change of load, and realize accurate control of power generation through real-time monitoring and calculation of the system, thus maintaining the stable operation of the power system.
Secondary frequency modulation can also adjust the frequency of the power system without difference, that is, through the feedback mechanism of the control system, the frequency of the power system can be accurately kept near the rated frequency. This is helpful to improve the stability of power system and reduce the influence of frequency fluctuation on users and power system.
Secondary frequency modulation can also be combined with other control strategies such as regional control deviation and optimal power flow to improve the performance and efficiency of power system. These control strategies can be optimized and adjusted according to the actual situation of the power system to achieve the best operation of the power system.
To sum up, secondary frequency modulation plays an important role in power system, which can maintain the stable operation of power system and improve the performance and efficiency of power system.