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Small hydropower plays a pivotal role in flood retention and storage， runoff regulation， energy mix improvement， ecological environment protection acceleration， income increase of local farmers， and infrastructure enhancement. This paper expounds the necessity of the peak and valley time division adjustment based on the specific condition of a municipal power grid. Then the peak-valley time division adjustment situation and the FIT （feed-in tariff） of the small hydropower are provided. Finally， based on the review of measured data， including gateway electricity consumption and the output of small hydropower， the influence of the peak and valley time division adjustment on small hydropower is analyzed. The results show that the adjustment of peak and valley time can change the power generation behavior of small hydropower and ease the condition of peak-valley inversion in the gateway between day and night.

The construction of market power regulation is one of the critical elements of the current market construction and supervision system construction in China. Firstly， this paper summarizes the detection methods， mitigation measures， and evaluation indicators of overseas electricity market power and compares and analyzes the advantages and disadvantages of structural processes and behavior-influence methods. Then， the problems and challenges faced by China are summarized from the perspective of power supply distribution， power supply mix， network frame power flow， and bidding strategy. The paper analyzes the problems and challenges faced by China’s market power control construction. Furthermore， it points out that China’s market power regulation on the power generation side should take power plants as the primary control object. A regulation system that combines events before and after with emphasis on the behavior-influence method is established. Finally， from the market design and construction perspective， measures to mitigate market power are proposed， and an evaluation index system for market power is given to provide a reference for the construction of market power regulation in China.

As China has declared its pledge on peak emission and carbon neutrality and the target of building a new power system， the new energy in China is undergoing a period of rapid development. However， since the subsidies for new energy continues to decrease， it is widely recognized that new energy consumption and the revenues should be addressed through a market-oriented way. The paper simulates and estimates new energy participating in market trade by “quoted volume without quotation” based on the trading mechanism of electricity spot market in Zhejiang province. The results show that new energy， through rational safeguarding of utilization hours and rational utilization hours consumption， can ensure its own revenues and in the meantime reduce subsidies by participation in market； in contrast to wind power， solar PV is more receptive to electricity spot market.

In the centralized spot market, each participant pursues the maximization of economic benefits, which leads to the operation condition of the power grid closer to the security boundary. Thus, in this paper, a novel approach to security margin assessment of the centralized spot market is proposed. By proceeding from the mechanism of influence of load variation on power flow, the relationship between power flow transfer characteristics and the security margin of the power grid is explored. Then, on the basis of information entropy theory, the power flow transfer balancing evaluation index of the power grid is established. And this index is applied for security margin assessment of the power grid in the environment of the centralized spot market. Results of an IEEE 14-bus system case study have validated the effectiveness and quickness of the proposed method. Meanwhile, in accordance with the analysis results, it is proved that the proposed method is capable of accurately identifying the critical power transmission and transformation equipment affecting the security margin of the power grid, which is helpful to identify the potential risks of the operation of the power grid in advance.