What are the conditions for using two generator sets in parallel

The condition for parallel use is that the instantaneous voltage, frequency, and phase of the two machines are the same. Commonly known as' three simultaneities'. Use a dedicated parallel device to complete the parallel operation. It is generally recommended to use fully automatic parallel cabinets. Try not to manually merge machines. Because the success or failure of manual parallel operation depends on human experience. Based on more than 20 years of experience in power work, the author boldly states that the reliable success rate of manual parallel operation of diesel generators is zero. We must not apply the concept of manual parallel operation to small power systems, as the protection levels of the two are completely different.