This paper compares the advantages and disadvantages of closed water cooling systems and open water cooling systems in terms of heat transfer efficiency, footprint, water consumption, and cost. The heat transfer capacity, site environmental conditions, inlet temperature of the phase modulator heat exchanger, and other requirements are taken into account for installing a phase modulator at a certain converter station, as well as the economic investment and operational factors. It is ultimately determined that the external water cooling system for the phase modulator at the converter station adopts an open water cooling scheme. The design scheme of external cooling system for the phase modulator is given in this paper, hoping to provide reference for the selection and design of the external cooling system for phase modulator in subsequent projects.

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.

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 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.

The grounding wire is an important equipment for ensuring the personal safety of power operators. Traditional grounding wire lacks informationization and intelligent management methods. There is no closed-loop management method for the extraction and return of grounding wire, which can easily lead to misconnection, no connection, and without returning, bringing huge risks to the safe and stable operation of the power grid. This article focuses on the Internet of Things (IoT) and intelligent transformation of grounding wire, grounding wire cabinet, and grounding pile. The design covers the full-process control system architecture covering the “cloud-network-edge-end”, and the full-process control system of grounding wire and intelligent monitoring device are developed. Through the method of edge IoT proxy cross regional collaboration, the consistency of the real-time status of grounding wire, grounding wire cabinet and grounding pile and business data between the security Ⅳ region and the Internet region is achieved. Based on cross regional collaboration of data, cross regional data collection and panoramic monitoring of grounding wire are achieved to ensure accurate grounding connection, improving the safety and work efficiency of on-site operators, and providing guarantees for the safe and stable operation of the power grid.

The assignment of work orders is an essential part of the power operation and maintenance management system. Timely and accurate assignment methods can effectively improve the efficiency of work order circulation. Based on in-depth analysis of the characteristics of work order management in the field of power operation and maintenance, this article proposes an automatic assignment model for power operation and maintenance work orders based on fit degree. The model adopts criteria importance though intercrieria correlation (CRITIC) weighting method and fuzzy comprehensive evaluation to calculate the compatibility between operation and maintenance personnel and work orders, determine the optimal candidate for work order assignment, and then achieve automatic assignment of work orders. The practical application results show that compared to manual assignment, this automatic assignment model can effectively improve the efficiency and accuracy of work order assignment.

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.