Ultra-high Voltage Power Grid Research Articles

Economic Assessment and Policy Analysis on Wind Energy Development in China

Considering rapid development and emerging new challenges of China's wind energy development, this paper summarizes and analyzes five critical problems. First, according to an economic potential assessment, if the feed-in tariff is set 0.60 Yuan/kWh, the economic potential of wind electricity of China will reach 6.63[Formula: see text]PWh, it could meet as much as 2/3 of total power demand by 2030, thus the targeted wind power proportion in future high renewable energy penetration can be achieved. Second, wind energy is abundant but little consumed in Northwest, Northeast and North China while it is insufficient in South and East of China, where grid-connection condition is well. Due to this reverse distribution pattern of wind power endowment and consumption in China, grid-connection transmission must be strengthened in the future, particularly the West–East and North–South power transmission projects must be pushed forward. Third, to address the issue of increasing wind energy curtailment in Northeast, Northwest and North China, stimulating local consumption of wind power by multiple ways is a possible solution in the short term, however, in the medium and long run, it is necessary to accelerate the construction of Ultra-High Voltage power grid in order to expand power transmission to other provinces and regions. Fourth, a new electricity market mechanism should be established as the fundamental measure of promoting new energy development, while green certificate trading market and carbon trading market will form the basis for such market mechanism in the long run. Fifth, though wind power development can bring multiple benefits to economy, employment, and environment, large-scale wind power development will, to some extent, affect local and regional climate. As global warming continues, the wind power resource distribution of China and the world may experience significant changes.

Transmission Technologies and Operational Characteristic Analysis of Hybrid UHV AC/DC Power Grids in China

In order to solve the contradiction between demand and distribution range of primary energy resource, Ultra High Voltage (UHV) power grids should be developed rapidly to meet development of energy bases and accessing of large-scale renewable energy. This paper reviewed the latest research processes of AC/DC transmission technologies, summarized the characteristics of AC/DC power grids, concluded that China’s power grids certainly enter a new period of large -scale hybrid UHV AC/DC power grids and characteristics of “strong DC and weak AC” becomes increasingly pro minent; possible problems in operation of AC/DC power grids was discussed, and interaction or effect between AC/DC power grids was made an intensive study of; according to above problems in operation of power grids, preliminary scheme is summarized as fo llows: strengthening backbone structures, enhancing AC/DC transmission technologies, promoting protection measures of clean energ y accessing grids, and taking actions to solve stability problems of voltage and frequency etc. It’s valuable for making hybrid UHV AC/DC power grids adapt to operating mode of large power grids, thus guaranteeing security and stability of power system.

A novel evaluation method of societal benefits of ultra high voltage power grid optimizing power energy allocation

Although Ultra High Voltage (UHV) power grid requires heavy investment, it can also produce vast social economic benefits by optimizing power energy allocation. Owing to the existing controversy over the economy of the UHV power grid, it is necessary for policymakers to propose a scientific method used to comprehensively analyze huge costs and benefits caused by the UHV power grid. In this paper, Life Cycle Cost (LCC) is introduced to analyze cost dimensions of the UHV power grid and shadow price theory is used to evaluate huge potential social benefits brought by UHV power grid. Based on these shadow prices, social benefits of UHV power grid are put forward from aspects of saving installation benefit, saving coal-fired benefit, power loss reduction benefit, short-circuit current reduction benefit, sustainable development benefit, and social resource distribution optimization benefit. Some evaluation indexes for social benefits based on input-output analysis table of the LCC mode are calculated to be comparable with those of the traditional cost mode. A certain UHV power grid of China is applied to verify the effectiveness and feasibility of the proposed evaluation method.

UHV AC and DC Coordinated Operation Techniques Based on Continuous Simulation

In the process of China's ultra high-voltage (UHV) construction, Henan UHV power grid is the important part. Summer great load mode of Henan power gird is chosen as the typical method. In the background of completing Nanyang UHV extension project, based on single pole running and double pole running of Hami-Zhengzhou UHVDC project respectively, it is simulated and analyzed. The results indicate that power grid cannot maintain stability when single pole block fault or double pole block fault occurs. Through theoretical analysis and simulation, under UHV AC running certain limit, HVDC latching grid is stable. Under UHV DC running certain limit, HVDC latching grid is stable. Based on continuous simulation, this paper obtained the coordinated operation of area UHV AC and DC.

Shunt Reactors Compensation Research of UHV Accessed to Jiangxi Power Grid

Jiangxi ultra high voltage (UHV) accessed program is introduced. Based on uniform transfer equation, UHV π-type equivalent circuit is derived by considering the distributed parameter characteristics of UHV transmission line without conductance. Based on advanced digital power system simulator, the relationship of shunt reactor and steady-state voltage, as well as the relationship of shunt reactor and transient voltage, is achieved by using electromechanical and electromagnetic hybrid simulation, where the UHV between Hubei and Jiangxi is considered. Influences of shunt reactors’ location and the degree of compensation on UHV’s steady-state voltage and transient power frequency overvoltage are analyzed. The Logical results provide a meaningful guidance for the introduction of UHV power grid into Jiangxi power grid.

Building resilient power grids from integrated risk governance perspective: A lesson learned from china's 2008 Ice-Snow Storm disaster

In the past three decades, the electric energy industry made great contribution to support rapid social and economic development in China, and meanwhile has been grown at the highest rate in the human history owing to the economic reform. In its new national development plan, more investment has been put into installation of both electricity generating capacity and transmitting capacity in order to meet fast growing demand of electric energy. However, energy resources, both fossil fuel and renewable types, and energy consumption and load centers in China are not evenly distributed in both spatial and temporal dimensions. Moreover, dominated by coal as its primary energy source, the whole eastern China is now entering an environmental crisis in which pollutants emitted by coal power plants contribute a large part. To balance the regional differences in energy sources and energy consumption while meeting the steadily increasing demands for electric energy for the whole country, in addition to increase electric generating capacity, building large-scale, long-distance ultra high voltage power grids is the top priority for next five years. China is a country prone to almost all kinds of natural disasters due to its vast, complex geographical and climatic conditions. In recent years, frequent natural disasters, especially extreme weather and climate events, have threatened the safety, reliability and stability of electric energy system in China. Unfortunately, with fast growth rate but lacking of risk assessing and prevention mechanism, many infrastructure constructions, including national power grids, are facing integrated and complex economic, social, institutional and ecological risks. In this paper, based on a case analysis of the Great Ice Storm in southern China in January 2008, risks of building a resilient power grid to deal with increasing threats from extreme weathers are discussed. The paper recommends that a systematic approach based on the social-ecological system framework should be applied to assess the risk factors associated with the power grid, and the tools to deal with complex dynamic systems need to be applied to deal with constant changes in the whole social-ecological system.

Exploration of AGC Control Mode for North China-Central China-East China UHV Synchronous Power Grid

With the continuous construction of ultra high voltage (UHV) power grid, East China-Central China North China will be interconnected via UHV lines to be a UHV synchronous grid in the future. Further expansion of the grid scale, the existing active power and frequency control mode has been unable to adapt to the new features. Based on the future structure of North China-Central China-East China synchronized power grid, the article built the whole network of the AGC control model using PSD-FDS full dynamic simulation program. By the simulation of examples, the problems of AGC control mode for UHV synchronous power grid has been pointed out visually. Finally, the paper presented an ideal AGC control mode called centralized control mode to deal with the new challenge.

A Novel Method of Static Security Analysis Based on Multithread Technology

With the UHV (Ultra High Voltage) power grid construction and the interconnection of regional power grids, the scale of power grids in China is increasing rapidly. At the same time, significant uncertainty and variability is being introduced into power grid operation with the integration of large-scale renewable energy in power systems. All of these pose an enormous challenge to the operation control of power systems in China. For a long time, online static security analysis, as an important part of EMS (Energy Management System), has been an effective tool for power grid operation. However, it is increasingly difficult for traditional static security analysis in serial computing mode to be online applied in bulk power grids in China. A new practical parallel approach for online static security analysis is put forward in this paper. A multithread parallelism is introduced into contingency screening, detailed contingency evaluation and decision support for reducing the execution time. By employing the multithread technology, the hardware resources of multi-processor/multi-core computer can be fully used and the program can be speeded up effectively. The performance of the parallel static security analysis is demonstrated by tests on two large-scale power systems. The test results show that the proposed method can be online applied in real bulk power grids.

The Comparative Study on Influence on the Northeast China UHV Planning Power Grid Induced by Different Kind Geomagnetic Storms

Along with the UHV construction scheme, China will form a large number of transmission lines which have the characteristics of the ultra-high voltage, large-capacity, long-distance. Because the UHV power grid transmission line parameters and the structure of the grid and the transformer are different from the other power net, Geomagnetic storms will affect the UHV power grid more, the work have important significance to the assessment of the ultra-high voltage power grid level and influence. The impact of different storms on the grid are also different .Based on the power flow mechanism of the GIC, different data and network parameters of geomagnetic storms, the evaluation model of the GIC is established ,we assess the result of the GIC induced by the geomagnetic storms happened on November 2004 and December 2006 in the 2020 planning ultra-high voltage power grid, find out the greatest impact transformer substation and the timing analysis results of the grid compare the different impact of different storm.. The comparison of the analysis results is helpful for understanding the different kind geomagnetic storms and the regional features of GIC.

Measure Characteristic of UHV Power Frequency Voltage Ratio Standard

In order to meet the urgent needs of voltage measurement traceability and transfer in the construction of ultra-high voltage power grid, 1000kV series standard voltage transformer is developed as the standard instrument, and then its measurement characteristics is tested. According to the theory and construction of the series power frequency voltage ratio standard, semi-insulating transformer voltage summation is proposed to make the voltage ratio measurement of SSTV whose accuracy can reach the 0.02 level trace to the source of national power frequency ratio standard of 500kV successfully. The compatibility is better than compared to traditional voltage coefficient measuring method.

Geomagnetically Induced Currents in the High-Voltage Power Grid in China

With the operation of long transmission lines, unknown severe vibration and noise in transformers have sometimes been observed at the Shanghe substation and at the Ling'ao nuclear power plant in China. This paper gives a comparison of magnetic-storm recordings and measured transformer neutral current data and confirms that the disturbances were caused by geomagnetically induced currents (GICs). On November 7 and 9, 2004, the maximum GIC at the Ling'ao nuclear power plant was 47.2 A and 75.5 A, respectively, which are both larger than the neutral DC current caused by the HVDC monopole operation. The analysis of GIC data indicates that the GIC level is mainly determined by the geomagnetic-field variation rate, but the earth conductivity and power grid parameters are also important factors affecting GIC values. The data show that the GIC level is higher at the Ling'ao nuclear power plant than at the Shanghe substation. The reason is considered to be related to the grid structure and to the coast effect. Furthermore, because of smaller resistances, longer transmission lines, a larger scale, and the adoption of single-phase transformers, the influences of GIC on the ultra-high voltage power grid being constructed in China need to be studied more urgently.