Under the backdrop of the new power system, traditional generation companies may leverage market mechanisms to exercise market power and gain additional profits. To prevent potential market manipulation strategies by generators, from a regulatory perspective, a comprehensive strategy simulation model considering multiple market behaviors is proposed to simulate the behavior of power generators.. Firstly, the coupling relationships of multi-side markets in the carbon context are analyzed, and factors potentially influencing market clearing are examined based on market mechanisms. Secondly, recognizing the limitations of single behaviors, the model holistically considers various manipulation which tactics generators might employ, including capacity withholding, price bidding, and collusion. A dual-layer bidding model is constructed, consisting of the generator decision-making layer and the market clearing layer.Then, given that decision variables include both discrete and continuous types, a hybrid approach combining DDQN and TD3 algorithms is adopted to solve the two-stage action decision problem involving collusion intentions and information bidding, simulating the evolution of each generator′s strategy. Simulation results reveal that in a multi-side coupled market environment, generators tend to form strong alliances with competitors possessing bidding advantages, enabling tacit collusion to manipulate electricity prices and capacity, thereby reducing market efficiency. Additionally, it is found that reasonable market mechanisms can partially mitigate capacity withholding and alleviate market power, offering valuable insights for market regulation.