The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP) units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS), which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP) and the buildings’ thermal inertia (BTI), abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

Active frequency response (AFR) control is needed in current power systems. To solve the over-frequency problems of generators connected to non-disturbed buses during the AFR control period, the generators should be clustered into coherent groups. Thus, the control efficiency can be improved on the premise of ensuring control accuracy. Since the influencing factors (such as the model parameters, operation modes, and disturbance locations, etc.) of power system operation can be comprehensively reflected by the generator frequency, which is easily collected and calculated, the generator frequency can be used as the coherency identification input. In this paper, we propose a coherency identification method of AFR control based on support vector clustering for a bulk power system. By mapping data samples from the initial space to the high-dimensional feature space, the radius of the minimal enclosing sphere that can envelop all the data samples is obtained. Moreover, the coherency identification of generators is determined for AFR control according to the evaluating method of AFR clustering control effects and the evaluating index of cluster compactness and separation. The simulation results for the modified New England IEEE 10-generator 39-bus system and Henan power grid show that the proposed method is feasible and effective.

Aqueous zinc‐ion batteries (AZIBs) provide a new scheme for large‐scale electrochemical energy storage systems by virtue of high safety and cost‐effectiveness. However, the application of MnO ₂ cathodes in AZIBs is hindered by the irreversible structural collapse originating from the Jahn–Teller effects of Mn ³⁺ and the sluggish diffusion kinetics. Herein, an Al/N co‐doping strategy is proposed to overcome these limitations. Partial Mn ³⁺ is substituted by Al ³⁺ in the Al/N co‐doped MnO ₂ (Al/N‐MO), where the Al ³⁺ ions disrupt the long‐range ordering of Mn ³⁺ and exert a pinning effect within the lattice to restrain the axial deformation of [Mn ³⁺ O ₆ ] units during discharge, thereby mitigating the Jahn–Teller effects. The substitution of lattice oxygen by less electronegative N atoms counteracts the lattice strain induced by Al‐doping and reduces the diffusion resistance for carriers within the tunnels, simultaneously triggering the optimization of the band gap. Furthermore, the substitutional co‐doping of Al and N induces grain refinement, provides abundant grain boundaries, and widens tunnel size, significantly boosting pseudocapacitive storage. The tailored Al/N‐MO cathode demonstrates decent electrochemical performance (315.3 mAh g ⁻¹ at 2 A g ⁻¹ and a residual capacity of 292.6 mAh g ⁻¹ over 3000 cycles), as well as stable cycling over 130 days with a quasi‐solid‐state electrolyte.

After power disturbances occur in power systems, the frequency response presents significant spatial-temporal characteristics. The current situation of asynchronous frequency response in different areas determines that there is room for improvement in the frequency regulation capability of interconnected power systems. Due to the optimal operation of power systems through multi-stage coordinated operation, this paper proposes a multi-stage coordinated active frequency response (CAFR) control strategy based on three lines of defense for frequency stability of power systems, aiming at safety and economic coordination. In the prevention control stage, the regulation capacity is reserved by purchasing the frequency regulation capacity in advance; In the emergency control stage, the frequency response spatial-temporal characteristics are utilized to enhance the frequency regulation capability of the system through feedforward active control; In the correction control stage, penalty items are set to avoid affecting system safety and triggering under frequency load shedding (UFLS). Both numerical example analysis and simulation verification show that the proposed active frequency response (AFR) control strategy for AC/DC hybrid power systems based on three lines of defense coordination is superior to the passive frequency response (PFR) mode in terms of security, and is more superior to the single stage operation control in terms of economy, with significant improvement in overall control effectiveness.