Self -sufficient time means that energy storage equipment can maintain normal operation and ensure the duration of power supply performance in the absence of energy supplementary energy.

This is easier to understand for independent distributed power generation systems. For example, for an independent photovoltaic battery system, the battery should ensure that the load can still work normally when the sunlight is continuously lower than the average. Assuming that the battery is fully charged, when the degree of light is lower than the average, the power generated by the photovoltaic battery component cannot fully meet the load demand. The battery will release a part of the energy Not full. If the light illuminance is still lower than the average the next day, the battery still needs to discharge to supply the supply load, and the battery state of the battery continues to decline. Perhaps there are still three consecutive days and fourth day ... In order to avoid damage to the battery, this discharge process only allows a certain period of time until the battery's loading status reaches the specified danger value. The number of days that the system can still work normally without any external energy is the number of self -sufficient days.

For the distributed power generation system running in the grid, in order to reduce the impact of random problems of distributed power supply on the power system, energy storage and power prediction solve the problem of random volatility of photovoltaic power. The energy storage capacity can Design the difference in power. Without any foreign energy, the system rely on the continuous self -sufficient time between the energy storage compensation to compensate the actual output power and the predicted power, which is mainly affected by the accuracy of the predicted model and the control of energy storage and power storage.