China’s 10-year progress in DC gas-insulated equipment: From basic research to industry perspective

The construction of the future energy structure of China under the 2050 carbon-neutral vision requires compact direct current (DC) gas-insulation equipment as important nodes and solutions to support electric power transmission and distribution of long-distance and large-capacity. This paper reviews China's 10-year progress in DC gas-insulated equipment. Important progresses in basic research and industry perspective are presented, with related scientific issues and technical bottlenecks being discussed. The progress in DC gas-insulated equipment worldwide (Europe, Japan, America) is also reported briefly

A Two-Dimensional Cloud Model for Condition Assessment of HVDC Converter Transformers

Converter transformers are the key and the most important components in high voltage direct current (HVDC) power transmission systems. Statistics show that the failure rate of HVDC converter transformers is approximately twice of that of transformers in AC power systems. This paper presents an approach integrated with a two-dimensional cloud model and an entropy-based weight model to evaluate the condition of HVDC converter transformers. The integrated approach can describe the complexity of HVDC converter transformers and achieve an effective assessment of their condition. Data from electrical testing, DGA, oil testing, and visual inspection were chosen to form the double-level assessment index system. Analysis results show that the integrated approach is capable of providing a relevant and effective assessment which in turn, provides valuable information for the maintenance of HVDC converter transformers

Calculation of inlet capacitance for long-duration induction voltage test of single-phase three-winding converter transformers

The converter transformer is one of the core equipment in the high-voltage DC (HVDC) transmission project. The capacity of the converter transformer is much larger than that of an ordinary AC transformer, and its main function is to convert the AC system voltage to the phase change voltage required by the converter. The long-duration induction voltage test is an important technical means to assess the insulation strength of electrical equipment, and the calculation of the inlet capacitance of the converter transformer in the test design is extremely critical. This paper conducts circuit and mathematical modeling based on the structure of a single-phase three-winding converter transformer, calculates the equivalent capacitance between each winding of the converter transformer and each winding to ground by the model, and uses each equivalent capacitance to calculate the voltage added inlet capacitance, then obtains the appropriate compensation inductance. Moreover, the calculated inlet capacitance is verified by using the field test data, and the verification results show the reasonableness of the model. Finally, the calculation results are analyzed for errors and possible sources of errors are pointed out. This inlet capacitance calculation method has some universality and is expected to be promoted and applied in this field

cAMP Response Element Binding Protein Expression in the Hippocampus of Rhesus Macaques with Chronic Ephedrine Addiction

Background. Drug addiction is classified as a chronic relapse nature brain disease with complicated neurobiology mechanisms. There are an increasing number of researchers that are investigating the possible mechanisms for solving the thorny problem. Methods. The model of chronic addiction of rhesus monkey ephedrine was established, where changes in body weight and behavior were monitored. The expression of cAMP response element binding protein (CREB) in the hippocampus of rhesus monkeys was identified by real-time PCR and Western blot. Results. We were successful in establishing the chronic ephedrine addiction model in the rhesus macaques. They exhibited changes in body weight and behavior. Immunofluorescence showed that CREB was expressed in the nucleus of the hippocampus, and the expression of CREB mRNA and protein in the hippocampus were increased by real-time PCR and Western blot. The CREB positive expression in the hippocampus of the modeling group was significantly higher than in the control group. Conclusions. The changes of body weight and behavior of the rhesus monkeys after ephedrine chronic addiction were significant. The changes of CREB in the hippocampus of rhesus macaques with ephedrine chronic addiction are important molecular mechanisms, and the upregulation of CREB may be involved in the physiological pathology and behavior process in individuals with chronic ephedrine addiction

cAMP Response Element Binding Protein Expression in the Hippocampus of Rhesus Macaques with Chronic Ephedrine Addiction

Background. Drug addiction is classified as a chronic relapse nature brain disease with complicated neurobiology mechanisms. There are an increasing number of researchers that are investigating the possible mechanisms for solving the thorny problem. Methods. The model of chronic addiction of rhesus monkey ephedrine was established, where changes in body weight and behavior were monitored. The expression of cAMP response element binding protein (CREB) in the hippocampus of rhesus monkeys was identified by real-time PCR and Western blot. Results. We were successful in establishing the chronic ephedrine addiction model in the rhesus macaques. They exhibited changes in body weight and behavior. Immunofluorescence showed that CREB was expressed in the nucleus of the hippocampus, and the expression of CREB mRNA and protein in the hippocampus were increased by real-time PCR and Western blot. The CREB positive expression in the hippocampus of the modeling group was significantly higher than in the control group. Conclusions. The changes of body weight and behavior of the rhesus monkeys after ephedrine chronic addiction were significant. The changes of CREB in the hippocampus of rhesus macaques with ephedrine chronic addiction are important molecular mechanisms, and the upregulation of CREB may be involved in the physiological pathology and behavior process in individuals with chronic ephedrine addiction