Tao Huang's research while affiliated with State Grid Electric Power Research Institute and other places

Today, increasing communication of Internet of Things (IoT) devices, wearable sensors, healthcare applications and cloud providers provides power and energy consumption for high processing personal data and healthcare records. Cloud-edge data centers are processing enormous amount of electrical power resulting in high performance computing. One of the important challenges in this problem is Virtual Machine (VM) service placement that attempts to enhance energy management of VMs to cloud-edge service providers dynamically to support Service Level Agreement (SLA) metrics in IoT systems. Service placement is a very important issue because if VMs are not confident in the SLA of their critical data, IoT applications will not want to use existing resources safety. Providing a way to increase the Quality of Service (QoS) factors and energy efficiency of the service placement in the IoT environment is an important and critical issue because the use of IoT devices and wearable sensors increases energy consumption in human life in smart contracts. Therefore, this paper presents a hybrid Genetic algorithm and social spider optimization (GA-SSO) algorithm for an energy-aware service placement model in the IoT to manage data congestion and system safety. After conducting studies and comparisons, the accuracy and superiority of the proposed model were established. Experimental results show that the energy consumption with the proposed GA-SSO algorithm can be reduced 24% and we can achieve to the performance of QoS factors with fitness function 88% with compare to the other meta-heuristic algorithms.

The grounding grid of power equipment is the most basic overvoltage protection device for the power system. Before the design and construction of the power grounding grid, the power system generally uses a scaled-down model to verify the characteristics of the grounding grid. As the types and structures of grounding materials become more and more complex, there are one or more similar items in the grounding simulation test that cannot be scaled down. This paper takes the similarity test of a new type of grounding material-flexible graphite composite grounding material as an example. Firstly, the complete similarity theory of the grounding simulation test is deduced. Secondly, the source of similar distortion items is analyzed. Then, the distortion error of different similar items is analyzed. Finally, the distortion similarity test of the flexible graphite composite grounding material is taken as an example to verify the test error influence of the distortion similarity item of the grounding simulation. The research results of this paper can provide a reference for grounding simulation tests, and at the same time, they can be applied to similar tests in other fields.

During the long-term operation of electrical equipment, the insulation performance of applied SF 6 gas may be affected by humidity, pressure, and temperature. In this study, the collision cross sections of SF 6 and H 2 O are considered, including ionization, attachment, excitation, and elastic collision. In order to analyze the influencing factors of SF 6 insulation performance, discharge parameters are computed by the Boltzmann equation under different environmental conditions, including humidity, pressure, and temperature. It is concluded that with the conditions of 0.1 MPa and 300 K, the critical breakdown electric field increases by 1.23 kV/cm as the relative humidity increases from 0% to 80%. As the pressure increases from 0.1 to 0.6 MPa, the critical breakdown electric field increases by 451.07 kV/cm. However, temperature also has little effect on the insulation performance of SF 6 gas. The conclusions of this study have reference value for safe and stable operation of SF 6 insulated power equipment.

Restricted by cultivated land vegetation, road construction, and land acquisition compensation costs, the grounding electrode extension method is not applicable for grounding resistance reduction of some wind turbines in limited areas. A new grounding resistance reduction method is proposed and verified for wind turbines by connecting nearby wind turbine grounding grids. To study the efficiency of the proposed method, the grounding characteristics of connected grounding grids are calculated. Simulation results indicate that the grounding resistance of connected grounding grids is smaller than that of box extension grounding grids. The grounding characteristics of the grounding grid connection are affected by grounding current frequency and material parameters. The grounding grid connection increases the current dispersion area and reduces the ground potential rise of the grounding conductor.

The flexible graphite composite grounding electrode is a non-metallic grounding electrode with good electrical conductivity, corrosion resistance and non-ferromagnetic properties. In order to analyze the impulse characteristics of the graphite composite grounding electrode, this paper builds a frequency domain electrical network model and an equivalent radius iterative algorithm, considering skin effect, inductance effect, capacitance effect and spark discharge effect. The impulse characteristics of typical metal grounding electrodes and graphite composite grounding electrodes are analyzed by simulation. The research results show that: Compared with the traditional metal grounding electrode, the graphite composite grounding electrode has a smaller skin and inductance effect under the action of the impulse current, and a better current flowing capability; as the soil resistivity increases, the inductance effect and the skin effect are weakened, while the spark discharge effect is gradually enhanced and dominates. The spark discharge effect can effectively decrease the grounding resistance. The obtained critical value of the normalized parameter of 412 kA Ω, can be taken as the threshold to discriminate the conditions with dominate inductance effect from the conditions with dominant spark discharge effect.

Corrosion is an inevitable problem of metallic grounding grids. To propose an effective method avoiding the above corrosion, a new type of non-metallic grounding material was made in this paper. It is called flexible graphite composite grounding material, namely flexible graphite composite grounding material for short. It is made by high-purity flake graphite with a stranded wire hierarchical structure. And a series of experiments have been carried out to verify its feasibility as electrical grounding material, including material resistivity and its contact resistance measurement, temperature tolerance test, mechanical performance test, and scaled electrical grounding test of several typical electrical grounding grids. These experimental results all indicate that characteristics of the new flexible graphite composite grounding material can well meet practical electrical engineering requirements.

The grounding grid of power equipment is the most basic overvoltage protection device for the power system. Before the design and construction of the power grounding grid, the power system generally uses a scaled-down model to verify the characteristics of the grounding grid. As the types and structures of grounding materials become more and more complex, there are one or more similar items in the grounding simulation test that cannot be scaled down. This paper takes the similarity test of a new type of grounding material-flexible graphite composite grounding material as an example. Firstly, the complete similarity theory of grounding simulation test is deduced. Secondly, the source of similar distortion items is analyzed. Then, the distortion error of different similar items is analyzed. Finally, the distortion similarity test of the flexible graphite composite grounding material is taken as an example to verify the test error influence of the distortion similarity item of the grounding simulation. The research results of this paper can provide reference for grounding simulation test, and at the same time, it can be applied to similar tests in other fields.

With the development of long-distance transmission of higher voltage levels, the loss of reactive power on transmission lines is increasing. The dependence on the external electricity is also rising, so that the voltage stability problems of the receiving system have become increasingly prominent. Therefore, using dynamic reactive compensation technology can improve the operating characteristics of the power grid and improve the safety and stability of the system. Based on the electromagnetic transient data of East China Power Grid in 2025, based on the parameters of the new large-capacity synchronous condenser, the electromagnetic transient model of the synchronous condenser is established and simulated. The simulation results show that after the installation of synchronous condenser, the minimum voltage of ZP bus is improved to different extents, the voltage recovery time is reduced to different extents. It also plays a certain role in reducing the number of commutation failures. Therefore, the installation of the synchronous condenser can provide effective dynamic reactive support for the local power grid with high proportion of DC power, which can reduce the probability of DC commutation failure in the AC grid fault.

The environmental conditions affect the external insulation performance of power equipment. In order to study the physical characteristics of air discharge, the microscopic process of electron–molecule collision in the air based on the Boltzmann equation has been studied in this paper. The influence of humidity on the air gap insulation performance was also analyzed. The calculation results show that with the temperature 300 K and the pressure 1.0 atm, the electron energy distribution function and electron transport parameters varied with the air relative humidity. As the air relative humidity is increased by each 30%, the average electron energy decreases by about 0.2 eV, the reduced electron mobility decreases by about 0.25 × 10 ²³ [1/(V·m·s)], the reduced electron diffusion coefficient decreases by about 0.2 × 10 ²⁴ [1/(m s)], and the effective ionization coefficient decreases by about 4 × 10 ⁻²⁴ m ² . As the air relative humidity increases from 0% to 60%, the critical breakdown electric field increases by 1.22 kV/cm.