Compared to other primary equipments such as busbars, lines, and circuit breakers, transformers have a more complex structure and are the only equipment in the power system that connect different voltage levels. In addition, the influence of the Y/D transform makes the fault characteristics complex and variable, making it difficult to locate the fault point. The fault localization depends on the experience of the engineer. There is an urgent need for a complete automated fault location system. This article first classifies the possible situations that may cause transformer protection starting or tripping, and then sets fault localization criterion step by step. The criterion greatly enhances the automation level of transformer fault localization and has good engineering implementation value. The feasibility and accuracy of this method are proved through multiple sets of simulation waveforms.

This article analyzes the characteristics of single phase grounding faults and cross line grounding faults in the same tower double circuit line, as well as the impact of zero sequence mutual inductance on grounding distance protection, in response to the misoperation fault of under range longitudinal distance protection during a cross line grounding fault on the same tower double circuit line. It is concluded that the additional impedance caused by zero sequence mutual inductance is the fundamental reason for the reduction of grounding distance protection range and the refusal of protection. In order to solve the problem, an adaptive zero sequence mutual inductance compensation method is proposed. The new method based on the adjacent zero sequence current injection and local auxiliary judgement can enable the compensation adaptively. The performance of the proposed method is evaluated based on the real time digital simulation system, and results show that this method is valid.

In the context of the global traditional energy crisis and the urgent need to explore green, environmentally friendly, and sustainable new energy, in order to break through the limitations of the understanding of photovoltaic application environment, scope, and carrying capacity, a telescopic and high-efficiency solar roof collector device is developed to address energy challenges and promote energy conservation and emission reduction. This scheme adopts a comparative research and data analysis method to deeply analyze the compatibility between solar energy and automotive characteristics. Through self created design, it integrates efficient photoelectric conversion technology and flexible telescopic structure to ensure maximum collection of solar energy for photoelectric conversion. The experimental results show that the device has high photoelectric conversion efficiency, and numerical examples verify the effectiveness of the proposed scheme and the feasibility of fully utilizing solar energy and extending the service life of automobiles.

In the context of “dual carbon” goal, integrated photovoltaic storage and charging station (IPSCS) can effectively solve the problem of independent operation of multiple types of flexible resources. To enhance the collaborative consumption capacity of source load and reduce carbon emissions, this paper proposes a multi-timescale day-ahead operation strategy for IPSCS that considers carbon emission stratification and source load interaction. Firstly, hybrid prediction model and Monte Carlo method are applied to historical data to derive typical photovoltaic output and electric vehicle load scenarios, respectively. Secondly, the objective function of the mathematical model of the operation strategy of the integrated station is minimum comprehensive planning cost, minimum carbon emission, and maximum utilization of new energy. The model is solved using an improved whale optimization algorithm (IWOA) incorporating an opposition-based learning strategy and diversity variation processing. Finally, the rationality and effectiveness of the proposed strategy are verified through case analysis.

To meet the production demand for offline automatic stacking of large transformer cores, this paper researches on the feasibility of the double hole positioning system of the truss type transformer core laminating machine, introduces visual positioning technology and conducts data verification. In the paper, by means of building an actual architecture and combining corresponding control theories and algorithms, the performance, precision, stability and reliability of the system are analyzed and evaluated. The experimental data and analysis results based on practical application scenarios indicate that the system is feasible.

In order to solve the ground fault in ungrounded systems, this paper applies the differential protection method based on the “external signal generating device and feeder terminal unit” to the external signal ground fault selection technology, proposes differential protection method of ground fault detection criteria and action principles, and achieves segment selection on the basis of ground fault phase selection. Finally, the effectiveness of the method is verified through a case study, and the results show that the proposed fault discrimination method has high accuracy and can minimize the range of ground fault power outages, which can also improve fault handling efficiency and power supply reliability.

Ultra-high voltage AC power system usually uses standard lightning current parameters to calculate external overvoltage, and lightning observation data show that more than 80% of the lightning process is multiple lightning strikes, which is significantly different from the standard recommended waveform. Under the background of frequent multiple lightning accidents in ultra-high voltage AC system, it is urgent to put forward a rigorous and scientific evaluation method of multiple lightning parameters. Therefore, this paper takes a 500kV AC ultra-high voltage transmission system as the object, and proposes a multiple lightning current waveform parameter evaluation method considering the transient characteristics of the line from the extreme lightning conditions and the actual fault recording. The analysis shows that the fault recording inversion method can characterize the real multiple lightning strikes. Extreme multiple lightning strikes method analyzes the lightning current parameters under harsh conditions from the lightning resistance level of the cable. The waveform parameter evaluation method proposed in this paper provides a technical scheme for overvoltage analysis of ultr-high voltage transmission system in lightning-prone areas.