Zhaoyan Zhang's research while affiliated with Hebei University and other places

... However, especially in areas with abundant wind resources, such as Northern China, the wind curtailment phenomenon is in a dilemma because the electric power system is not flexible enough [4,5]. An integrated energy system has the advantages of high efficiency and economy, which can promote the consumption of local renewable energy [6] and improve the level of largescale development and utilization [7]. Enhancing flexibility through energy conversion is a key area in energy systems [8]. ...

... Aiming at the impact of the uncertainty of source load on the optimal scheduling in an integrated energy system (IES), based on hybrid resolution modeling and hybrid instruction cycle scheduling technology, three-time scales of day-ahead, intra-day rolling and real-time feedback optimization scheduling models are established [38]. Then, the chaotic gravitational search algorithm (CGSA) is used to solve the problem, and the composite coordination optimization operation strategy of IES with mixed time scales based on CGSA is proposed. ...

... The algorithm combines the stochastic wandering strategy, the balanced optimizer and the adaptive learning strategy of BP neural networks, aiming to overcome the limitations of traditional BP neural networks in practical applications. Zhang et al. [21] proposed a particle swarm optimization algorithm based on nonlinearly decreasing inertia weights and exponentially varying learning factors for optimizing the deep belief network, which is used for solving the early warning problem of wind turbine faults. Zhang et al. [22] established a BP neural network prediction model optimized based on dynamic cuckoo search algorithm for solving modern industrial equipment fault detection and early warning problems. ...

... Therefore, new energy grid connection inverters, electric transmission lines, and output filters constitute the weak current grid system. Standing from the perspective of the grid connection point, the impedance of the power system is relatively high, with Short Circuit Ratio (SCR) commonly less than 3, which is likely to cause system oscillations [1][2]. In recent years, multiple forms of oscillation problems related to new energy units occurred to varying degrees around the world. ...

... They successfully tested the approach and compared it with other methods using historical data from WTGs. Wang et al. [48] proposed a statistical method to filter noisy SCADA data and subsequently apply nonlinear state estimate technology to predict the temperature from a WTG. The detection of an abnormal condition was made when the predicted temperature deviated from the expected values based on historical data. ...

... A novel real-time coordinated energy control method based on fast Stackelberg equilibrium learning was presented for the effective coordination of a multi-area IES [15]. In the view of the transient characteristics of district heating network (DHN), an ultra-short-term optimization model was established for IES optimal scheduling [16]. Evidently, these studies complement applications of flexibility scheduling strategies with multiple dispatching periods and higher temporal resolution. ...

... In other words, a HEM system provides information on home energy consumption data concerning real-time and prepares the appliance schedule chart focusing on power consumption optimization at home [47]. Thus, any HEMS should have a simple but realistic algorithm behind it that has the advantage of significant bill reduction and maintaining user satisfaction [48]. Another objective of any HEMS should also be to increase user privacy and that means limiting the sharing of details on the amount of energy usage [49]. ...

... Detecting PDs can be achieved by measuring ultrasonic waves. Researchers have attempted PD detection using acoustic emission (AE) sensors [16,17] and Sagnac [18,19]. However, they still face the same drawback of being limited to point measurements. ...

... With the continuous increase in the assembly capacity of wind turbines, permanent magnet synchronous generator have seen significant development and application due to their high stability, efficiency, and strong dynamic performance [1][2]. Compared to traditional three-phase generator, five-phase permanent magnet synchronous generator (F-PMSG) have characteristics such as small phase current, phase redundancy, high power density, and high reliability, making them increasingly widely used in the field of wind power and becoming a research focus both domestically and abroad [3][4]. Direct-drive five-phase permanent magnet synchronous wind power generation systems often adopt a back-to-back dual PWM structure. ...

... After the distributed generation system represented by photovoltaic power generation is proposed, the application proportion of new energy generation system in power system is increasing. As the interface unit between photovoltaic array and power grid [2,3,4,5], it is particularly im-portant to be familiar with its operation state and improve its stability [6]. Power electronic converter is a strong nonlinear control system. ...