The output fluctuation of the thermal power unit is the biggest when the auxiliary regulation is only from the load side, and is relatively small when the frequency change rate is fast. The output of the energy storage system is small while the SOC consumption is small, and the frequency stability is not affected.
When the energy storage system must be charged under the condition of frequency regulation, the charge power absorbed by the energy storage system steadily decreases when the SOC is at a high boundary value, and it eventually cannot absorb the charge power when the SOC hits the critical value.
the integrated regulation strategy proposed in this paper determines the switching time and operating depth of the energy storage system and the flexible load, and makes rational and effective use of the frequency modulation resources to regulate, giving full play to their respective advantages.
The method of using flexible load on the load side and energy storage on the power side to regulate frequency is proposed. The depth limit of energy storage action is proposed, which clarifies the dead zone and the maximum output limit.
The auxiliary regulation from the power side alone makes the SOC of energy storage exceed the limit, exceeding the upper limit of SOC operation by 0.9. In the case of comprehensive regulation, the SOC is well maintained near the reference value. 5.
The output fluctuation of auxiliary regulation and comprehensive regulation only from the power side is small. The comprehensive regulation system not only maintains the SOC state of energy storage, but also restores the stability of frequency faster.