Analysis of basic conditions of the power grid interconnection among Xinjiang, Pakistan, and five Central Asian countries

1 Introduction

Xinjiang is an important hub of the Silk Road Economic Belt in the “Belt and Road” national strategy,and a key node of the interconnection of multinational power grids in the global energy Internet strategy [1-5].The geographical distribution of energy and power consumption in China is uneven,and the installed capacity of new energy sources in many parts of China,including Xinjiang,has exceeded the capacity of absorbing new energy fully.Grid construction will objectively form an interconnected trend of grid development in the future [6-8].Owing to the time and climatic differences in each region,difference in the peak load and valley load,and the difference in the power structure determined by energy resources,the grid interconnection operation will bring huge networking benefits.

Five Central Asian countries and Pakistan on the “Belt and Road” Economic Belt have different resources and load requirements.This demanded for power interconnection among these countries,and all countries have explicitly expressed their support for the policies and plans for power development.Xinjiang in China has abundant wind and solar resources; however,the abandonment of wind and solar is a serious problem.The five Central Asian countries surrounding Xinjiang are rich in clean energy resources and have strong complementarity with Xinjiang; however,there is a shortage of electricity in Pakistan.Therefore,the grid has great potential for interconnection and interoperability.Under the “Belt and Road” strategic guidelines,the establishment of transnational energy power internet through ultra-high voltage(UHV)technology will interconnect the resource elements of the five Central Asian countries and Pakistan with China,which will be conducive to the optimization of cross-border regional power distribution and help raise the capacity of the grid for the absorption of renewable energy,thereby significantly reducing the use of fossil energy [9-11].

Reference [12]studied the construction situation of the power facilities,introduced the present situation of power network and the power demand situation,and analyzed the opportunities and risks of power cooperation development in the five Central Asian countries.Reference [13]studied the cooperative development of hydro,wind,and solar energy,elaborated the opportunities and risks for the cooperative development of clean energy between China and the five Central Asian countries,and analyzed the investment opportunities in the clean energy market in the five Central Asian countries.Reference [14]proposed to send Xinjiang’s surplus new energy power to the Arabian region through ultra-high voltage direct current(UHVDC)lines and built a China-Arab “New Energy Power Wire.” It made investment estimation for the China-Arab interconnection line and investigated the practicality of the China-Arab power system interconnection.It shows that the time is ripe for the construction of the China-Arab interconnected power grid.After networking,it can produce significant economic and social benefits,but it still faces many challenges.

The development of the interconnected synchronous power grids will bring tremendous benefits:First,the development and utilization of a large hydropower,nuclear power,and renewable energy sources will be guaranteed; energy efficiency will be improved; and operating costs will be reduced.Second,the system reserve capacity will be reduced and multiple power supply complementary adjustments will be promoted,saving power generation.The third is to achieve a large-scale optimization of energy resources,and the fourth is to improve the overall efficiency,safety and reliability of the power grid.This paper analyzes the related policies of transnational power interconnection and interoperability in China and introduces the resource and load demand,energy structure,and power supply status in Xinjiang,Pakistan,and five Central Asian countries.Based on this,this paper analyzes the short-term and long-term advantages of the transnational interconnected power from the aspects of power multipotent complementarity and timespace complementation of load.Finally,the feasibility of interconnection and interoperability in Xinjiang,Pakistan,and the five Central Asian countries is analyzed based on the advantage of the UHV technology in China and the current practical basis of cross-border interconnection.

2 Analysis of relevant policies in China

Power cross-border interconnection is a model of cooperation and competition.Without cooperation,there is no interconnection,but without interconnection,there can be no real competition.When establishing a transnational interconnected power system,direct intervention by the government is mainly based on the country’s resource utilization and the exchange of electricity between countries,with a view to long-term interests.

In 2013,Comrade Xi Jinping proposed the “Belt and Road” strategy during his visit to Central Asia and Indonesia.The “Belt and Road” is a bridge and link that connects Asia and Europe.It also promotes the common development of Asia and Europe.The “Belt and Road” radiation scope covers the Association of Southeast Asian Nations(ASEAN),South Asia,West Asia,Central Asia,North Africa,and Europe.In the “Vision and Actions on Jointly Building Silk Road Economic Belt and 21st-Century Maritime Silk Road,” which emphasized “enhancing the interconnection and interoperability of energy infrastructure,jointly safeguarding the safety of transport routes such as oil and gas pipelines,and promoting cross-border development.” The construction of power and transmission corridors and active cooperation in the upgrading and transformation of regional power grids have brought significant opportunities for the planning and construction of the interconnected power grids in Xinjiang,and the five Central Asian countries and Pakistan.

On September 26,2015,President Xi Jinping officially announced at the United Nations Development Summit in New York:“China has proposed to explore the establishment of a global energy internet and promote energy with a clean and green manner to meet the global demand.” The global energy internet refers to a strong smart grid based on the smart grid,with the UHV grid as the main network,clean energy transmission as the leading factor,and the global connectivity ubiquitous [2].Chairman of State Grid Shu Yinbiao once stated that there were three key points for networking between China and its neighboring countries:First,the Silk Road Economic Belt Transmission Corridor,the construction of a power transmission channel from Xinjiang in China to the five Central Asian countries; second,establish Russia and Mongolia’s transmission channels to China; third,establish a networking channel with neighboring countries in the south.The construction of the global energy internet is highly in line with the “Belt and Road” strategy.It has become an important measure for the implementation of the “Belt and Road” and is an innovative development and substantial initiative of the “Belt and Road.” They are closely linked to each other and promote each other.Further,it also provides good opportunities and a huge market for the delivery and consumption of new energy in Northwest China.

As an important energy base in China,Xinjiang accelerates the construction of the UHV power grids,expands the scale of outsourcing of Xinjiang,optimizes the allocation of energy resources,eases the tension between the energy supply and power structure,realizes the transformation of predominant resources in an autonomous region,and promotes sustainable and healthy economic development and cleanliness of Xinjiang.

During the “13th Five-Year period,” Xinjiang’s power grid investment will reach 221 billion yuan.The party committees and governments at all levels of the autonomous region will support the construction of power grids in Xinjiang,strive to create favorable environment and development policies,fully understand the importance of speeding up the construction of power grids in Xinjiang.The construction of the power grids should be regarded as an important task for the modernization of infrastructure during the “13th Five-Year Plan.” In particular,Xinjiang must focus on the “three bases and one channel” vigorously to promote the UHV power grid construction,expand the Xinjiang power transmission channel,and build Xinjiang into a “Power Silk Road” that links the Chinese eastern regions and neighboring countries.

In the “Belt and Road” economic belt,the five Central Asian countries,Pakistan,and other countries have different resource and load demand,which enables power interconnection and interoperability across the countries.All the countries have clearly expressed their support for power development policies and planning.All this indicates that construction of the interconnected power grid between China and the five Central Asian countries and Pakistan with Xinjiang as the foothold is an important energy strategy,and it realizes large-scale development and wide-area consumption of clean energy within the “Belt and Road” economic belt.

3 National resource endowments and transnational complementary features

3.1 Xinjiang province of China

Xinjiang is rich in coal,wind energy,and solar energy resources,and has large-scale development conditions and rapid development of wind-solar resources.However,the phenomenon of abandoning wind and solar power is particularly serious.As of the end of October 2017,the power generation capacity of the Xinjiang power grid networked operation was 80.573 million kW,of which,the installed capacity of wind power was 18.354 million kW,accounting for 22.8% of the total installed capacity.The installed capacity of the solar power was 9.076 million kW,accounting for 11.3% of the total installed capacity.From January to October,2017,11.28 billion kWh of wind power was abandoned,and the rate of wind rejection was 29.2%; the amount of abandoned photovoltaic power was 2.36 billion kWh,and the rate of abandoned solar was 21.0%.

At present,the difference between the peaks and valleys of the power grid in the Xinjiang Province has reached approximately 30%,and it is gradually expanding.The peak-to-valley difference is expressed as:

Where,PL,max and PL,min represent the maximum and minimum values of the load,respectively.

The power loads have obvious time-varying characteristics.The principle of system balance is to regulate the change of the conventional power output to track the load change and maintain a dynamic balance.A basic condition of the power system for stable running is that the system’s capability of adjustment must be greater than the load change.Because of the resource characteristics of wind and solar,its output has randomness and volatility.The maximum daily fluctuation of wind power can reach 80% of the installed capacity,and it has a certain anti-peaking characteristics; photovoltaic power generation is subject to day and night changes,weather changes,and moving clouds,which is also intermittent and volatile.Therefore,for the Xinjiang power grid with large-scale access to renewable energy sources,the conventional power supply must not only follow the load changes,but also balance the output fluctuations of the renewable energy sources.When the output of the renewable energy exceeds the system’s range of flexible adjustment,the output must be controlled to ensure the dynamic balance of the system.At this point,the wind and solar will be abandoned.If the current unit output is PG,the maximum and minimum outputs of the unit are PG,max and PG,min,respectively; then,the system’s upward and downward flexibilities are expressed as:

The total amount of flexibility resources that a conventional power supply can provide is FG

Analysis is performed from the perspective of renewable energy integration,and if the system is required to fully integrate the renewable energy at time t,it needs to fulfil the following equation:

where KG is the minimum technical output factor for the conventional power supplies,PRES(t)represents the renewable energy output at time t,CG is the boot capacity of the regular power supply,k is the average output coefficient of the self-backup power plant,Cs is the boot capacity of the standby power plant.

If equation(5)is not satisfied,the system power balance can only be achieved by reducing the output of the renewable energy,that is,the wind and light are abandoned; at this time,the expression of the system power balance is

Where,represents the remaining amount of renewable energy at time t.

The renewable source consumption is closely related to system capability of adjustment.At present,the capacity of adjustment of conventional power unit in Xinjiang has been unable to meet the demand for the adjustment of renewable energy.

Fig.1 Installed capacity of wind and solar in Xinjiang

Fig.2 Abandoning of wind and solar in Xinjiang

To solve the problem of large amounts of abandoned renewable energy in Xinjiang,it is necessary to speed up the construction of the external transmission channels of the company and rationally utilize the complementary features of the resources of each country such that the joint output of the energy can be stabilized and the utilization rate of the renewable energy resources can be increased.

The ratio of the abandoned wind volume to the theoretical wind power generation is the abandonment rate:

Where,EAW ndicates the amount of wind abandoned,and Ew indicates the theoretical power generation of wind power.

3.2 Pakistan

The main characteristics of the Pakistan power grid include:First,the grid is a north-south longitudinal network.Second,Pakistan’s hydroelectric power is mainly in the north of Pakistan,and the thermal power is mainly in the south of Pakistan.The central areas lack power supply projects.Third,the load center is far from the main power source and supplying the power to the load center needs a long distance.Fourth,the power flow is affected by seasonal changes.

Pakistan’s economic growth has been rapid in recent years.The shortage of power supply is one of the most important factors that constrains Pakistan’s economic development.The lack of power generation is the main cause of Pakistan’s power crisis.Electricity shortages have caused a power outage for 8-10 h per day in the country throughout the summer.It is estimated that by 2020,the maximum load will increase to 30.82 million kW,with an installed capacity of 26.14 million kW,and the market space will reach 10 million kW by that time.In the long term,the electricity load will reach 120 million kW,while the available installed capacity is only 90 million kW; therefore,the market space will be expanded to 30 million kW.

Power generation in Pakistan is dominated by coal-fired power and hydropower.Owing to large population,in order to alleviate the problem of long-term power supply shortage,Pakistan should start from China,Central Asia and West Asia to survey the out-of-area power-receiving scheme.

Fig.3 Available generators and electricity load in Pakistan

Fig.4 Electricity insufficiency in Pakistan

3.3 The five Central Asian countries

3.3.1 Kazakhstan

Kazakhstan is rich in coal resources,and its coal reserves are second only to Russia and Ukraine in the world.Kazakhstan has a total installed capacity of 19,000 MW,of which the thermal power stations store 15817 MW,accounting for 83.3%; gas turbine power stations store 916.1 MW,accounting for 4.8%; hydropower stations store 2259.6 MW,accounting for 11.9%.Among the electricity production companies in Kazakhstan,70% use coal,15% use natural gas and heavy oil,and another 15% are hydroelectric power stations.In addition,its wind energy resources are relatively abundant,but the current development is limited.

In recent years,Kazakhstan’s economy has developed at a faster rate,and electricity demand has been booming.The electricity demand is increasing at a rate of 5%-6% per year.However,the development speed of its power industry lags behind.Although it has abundant hydro energy resources,it has limited development and there is still a power gap.It is estimated that by 2020,electricity consumption is expected to exceed 150 billion kWh,and the maximum annual electricity consumption growth rate will reach approximately 7.2%.In particular,the shortage of electricity in southern Kazakhstan will increase.The Kazakh government gradually introduced a series of policies to increase the development of the power industry,particularly in power projects such as hydropower,wind power and other renewable energy power generation,environmental protection,and other functions.The Kazakh government has a very active investment policy that provides good opportunities for cross-border interconnection.

3.3.2 Kyrgyzstan

There are numerous rivers and lakes in Kyrgyzstan,and the water resources are extremely abundant.The reserves rank third in the Commonwealth of Independent States(CIS)countries,only second to Russia and Tajikistan.At present,only about 10% of them are developed and utilized,and the development potential is huge.The total installed capacity of Kyrgyzstan is 3748 MW,of which the hydropower installed capacity is 3030 MW and the thermal power installed capacity is 718 MW.In recent years,Kyrgyzstan has made development of hydropower as a priority development strategy and encouraged investment in hydropower projects.However,the seasonal nature of water resources is evident.Therefore,it needs to complement each other’s resources.

The total installed capacity of electricity in Kyrgyzstan can basically meet the domestic,industrial,and agricultural production needs.From 2010 to 2020,Kyrgyzstan’s electricity demand is expected to grow at a rate of 3%-5% per year.It is expected that by 2020,the country’s electricity consumption will exceed 30 billion kWh,and the maximum annual electricity consumption growth rate will reach approximately 6.3%.It is estimated that by 2020,the country’s maximum load will reach 6000 MW,and the maximum load will increase at an annual rate of approximately 6.5%.

3.3.3 Uzbekistan

Uzbekistan has relatively abundant renewable energy resources,and the solar energy has the largest development potential among them during summers because the average daily sunshine duration is more than 10 h.However,currently,the utilization of solar energy and wind energy is not high.The main reason is that the cost of solar energy is higher than that of natural gas.The government also lacks development measures and plans to encourage the use of renewable energy.

Ukrainian power is mainly based on thermal power,with a total installed capacity of over 12400 MW,of which the thermal power installed capacity accounts for 88.2% of the total capacity,and the hydropower accounts for 11.8% of the total capacity.In addition to satisfying the economic development and living needs of its residents,the electricity in Ukraine is also exported to other countries in Central Asia.According to the current economic growth rate,it is estimated that by 2020,the country’s electricity consumption will exceed 90 billion kWh,maximum annual electricity consumption growth will reach 5.6%,and the maximum load will reach 16,000 MW and increase annually.The speed will increase by about 6.0%.

3.3.4 Turkmenistan

Turkmenistan is rich in oil and gas resources,water resources are scarce,solar energy resources are abundant,and the maximum daytime in summer can reach 16 h.However,due to the ultra-low prices of thermal energy and natural gas,investment in photovoltaic projects is hindered.The total installed capacity of the existing power stations is 4850.9 MW,of which the installed capacity of gas-fired power generation is 2857 MW,coal-fired power generation is 1592.7 MW,fuel-fired power generation is 400 MW,and hydropower is 1.2 MW.

Turkmenistan’s relatively abundant electric power resources can not only meet the needs of the country’s economic and social development,but also have the ability to export electric power to the outside world.According to the average annual growth rate of 3%-4%,the country’s electricity consumption is expected to exceed 30 billion kWh by 2020,maximum load will reach 5,500 MW by 2020,and maximum annual growth rate of the load will reach approximately 6.0%.Turkmenistan’s electricity is mainly exported to Turkey,Iran,Afghanistan,and Tajikistan,and is developing new markets.It is estimated to achieve an annual export of 6 billion kWh by 2020.

Because 80% of its territory is covered by deserts and has good basic conditions for photovoltaic and wind power,Turkmenistan plans to manufacture large-scale wind energy solar hybrid systems.In the past two years,the Organization for Economic Co-operation and Development and the Organization for Security and Cooperation in Europe have both held seminars on the development of renewable energy in Turkmenistan and studied the country’s best practices in solar energy development strategies.

3.3.5 Tajikistan

The total installed capacity of Tajikistan is 5,408 MW.Its hydro,wind,and solar resources are abundant,which enables the development of large-scale renewable energy sources.

Although Tajikistan is one of the countries with relatively abundant power resources in the CIS,there is a gap between Tajikistan’s electricity supply and demand due to shortages of power equipment and small and mediumsized power generation equipment.Tajikistan has a clear national strategy for the development of hydropower and specific implementation plans,such as the strategy for “rejuvenating the country through hydropower” and its accompanying “long-term plan for the development of small hydropower plants during 2007-2020.” In recent years,the Tajikistan government has also been vigorously developing electric power infrastructure,including the construction of large,medium,and small hydropower stations and power grids,transformation of existing power stations,and plans to export electric power to neighboring countries.From 2010 to 2020,Tajikistan’s electricity demand has been growing at the rate of 2-4% per annum.It is estimated that by 2020,the country’s electricity consumption will exceed 34 billion kWh.The power load has been growing at the rate of 2-3.8% per annum.It is expected that by 2020,the country’s maximum load will reach 6,300 MW.

3.4 Resource complementarity characteristics analysis

The multi-energy complementarity focuses on the use of the timeliness and spatiality of various energy sources to achieve the purpose of complementing each other’s.To achieve the purpose of alleviating the contradiction between energy supply and demand,rationally protecting natural resources,and promoting a virtuous circle of ecological environment,multi-energy sources are used to supplement each other’s energy supply.In addition,the multi-energy complementation is conducive to promoting clean energy production and consumption in the vicinity,reducing waste of wind,light,and water,and promoting renewable energy consumption.It is an important measure to improve the overall efficiency of the energy system [15-17].

In recent years,the economy of Central Asia has generally maintained a relatively high growth rate.And there is a strong complementarity among clean energy resources in Central Asia.On the annual time scale,in summer,the wind speed is low,the solar radiation intensity is high,and the hydropower is in a wet period in Central Asia.In winter,the solar radiation intensity is low and the hydropower is dry,but the wind power is at its highest level in the entire year.On the daily time scale,the wind speed is higher at night and early morning,whereas the solar radiation intensity is lower during this period.At noon,the solar radiation is at its maximum,whereas the wind speed is low during this period.

The classic wind power characteristic function is defined as follows:

Here,vc,vN,vo,Pw,N represent the cut-in wind speed,rated wind speed,cut-out wind speed,and rated power,respectively.

Photovoltaic output depends on the light intensity,as follows:

Here,IT indicates the light intensity at time T,IS indicates standard light intensity,YPV indicates rated power,and μ indicates the derating factor caused by other environmental factors.

In addition,the power supply side constraints include the following:

Here,PRES,max indicates the boundary value of renewable energy output,PG,min and PG,max indicate the boundary values of the flexible unit output,Rampu and Rampd indicate the boundary values of the unit climbing uphill and downhill.

Fig.5 Intraday multi-energy complementary schematic in Central Asia

Xinjiang is rich in wind and solar resources,but water resources are insufficient.Additionally,the flexibility of peaking units is extremely limited.These limitations have led directly to the severe abandonment of wind and solar resources.The interconnection of Xinjiang with the five Central Asian countries and Pakistan,to make full use of the multi-energy complementary advantages,can not only reduce the start-up of thermal power generation and increase the capacity for renewable energy integration in Xinjiang,but can also transport surplus electricity to Pakistan to ease the predicament of local power shortage.

Xinjiang has the advantages of adequate resource reserves and great delivery potential,and thus can be used as the main power supply.Kyrgyzstan and Tajikistan are rich in water resources,and as hydropower is vulnerable to seasonal effects,it can be used as a receiver to absorb renewable energy from other countries during the dry season,and abundant water resources can be used for peak load adjustment to maximize water use efficiency.Kazakhstan has sufficient thermal power but limited development of renewable energy,and its thermal power can serve as a shared backup for interconnected countries.Pakistan is the main receiving country because its electricity is in short supply.At maximum load,the unit rotation reserve constraint is:

Where,H indicates the system backup capacity.

Fig.6 Overall judgement of complementarity of each country

In the long-term perspective,the focus of the interconnection between Xinjiang and the five Central Asian countries and Pakistan will be shifted from energy complementarities among countries and mitigation of power shortages to a clean-dominated,co-constructed,and shared modern energy supply.In the future,the five Central Asian countries will develop their wind,solar and water resources on a large scale.With their strong complementary characteristics,not only can they significantly reduce the use of fossil fuels in countries with thermal power as their major source of electricity and maximize the realization of clean alternatives,but they can also promote the renewable energy integration in Xinjiang and solve the problem of power shortage in Pakistan in a clean and environmentally friendly manner.

4 Load complementary characteristics

In recent years,the load growth level of various regions has stabilized and the load of the five Central Asian countries and Pakistan has also increased at the rate of 5-6% per year.The power load in Xinjiang has been increasing rapidly in recent years; the maximum load was 14.78 million kW in 2017.However,Xinjiang still has the phenomenon of substantial number of abandonments of wind and solar resources due to imperfections in the renewable energy integration mechanism.

Here,PL_sum(t)indicates the total load of all interconnected areas at time t,PL,n(t)indicates the load of the nth area at time t,N indicates the number of interconnected areas,and ntΔ ndicates the time difference between regions.

The space-time complementarity of load is an important factor affecting the renewable energy integration.The spacetime complementarity between regional loads is the transfer of system loads in different regions to achieve the purpose of expanding the range of renewable energy integration for power systems.

The increase in electricity after the replacement of electrical energy is defined as:

Where,PD(t)indicates the equivalent power of the electric energy substitution at time t.

The load after n years in a certain area can be defined as:

Where PL0 is the base year load,i is the annual load growth level.We consider the load shift as line exchange power.

Here PRES is the renewable energy output,PG is the thermal power unit output,and PLine is the line transmission power.The input is positive and output is negative.

Tajikistan,Uzbekistan,Turkmenistan,and Pakistan are all in the fifth time zone in the east,and they have a three- hour time difference with Beijing.Considering the impact of the interconnection between Xinjiang and somewhere in eastern China,the space-time complementarity of the load is used to promote the renewable energy integration in Xinjiang.Fig.8 shows the typical load curves of a place in eastern China,Xinjiang,and Pakistan after processing the time differences.There are significant complementary characteristics.

Therefore,based on the establishment of a crossregional interconnection system,it can make full use of the relative time difference of each system load and reduce the peak-to-valley difference of the entire system to achieve the best match between the load curve and power output characteristics.

5 Technical feasibility

Fig.7 Trends in power consumption in various countries

Fig.8 Typical daily load curves of somewhere in eastern China,Pakistan,and Xinjiang

(1)Ultra high voltage(UHV)transmission technology.The UHVDC and AC transmission technologies of China are mature,stable,and reliable,thereby laying a solid foundation for inter-regional grid connection and operability.China began a comprehensive and in-depth study of 800 kV UHVDC transmission engineering technology in 2004 and completed breakthrough in DC high voltage,high current,high power transmission technology,and equipment.The 800 kV DC transmission power has reached 8,000 MW and economic transmission distance is 2,400 km.Therefore,the UHV transmission can be used as the main technology for the realization of the main grids of interconnected power grids in Xinjiang,the five Central Asian countries,and Pakistan.

Table 1 Power transmission channels in Xinjiang

Time Transmission channels Voltage class /kV 2010 Xinjiang—northwest 750 2014 Hami—Zhengzhou ±800 Under construction Changi—Guquan ±1100 13th Five-Year period Zhundong—Chengdu ±1100 Zhundong—Wannan ±1100 Hami—Chongqing ±800 Yili—Pakistan ±800

The line constraints can be def ined as:

Where,PLine,min and PLine,max represent the boundary value of line transmission power.

(2)International Practice of Transnational and Transcontinental Interconnection.European Network of Transmission System Operators for Electricity(ENTSO-E)includes five synchronized grid regions in continental Europe,Northern Europe,Baltic Sea,United Kingdom,and Ireland.In addition,it also includes two independent systems in Iceland and Cyprus.ENTSO-E is made up of 34 European member states and the main grid voltage level is 400 kV.The transnational power trading volume is considerable and resources are optimally configured.The Russia-Baltic interconnected power grid covers a series of states of CIS and Baltic across 8 time zones and currently covers the largest area.ENTSO-E and Russia-Baltic interconnected power grid provide practical foundations for the construction of transnational interconnected power grids [19-21].In addition,exploration pioneers,such as the North America United Connected Power Grid and the Desert Solar Energy Project have also provided particularly important practical foundations for the concept of interconnectedness between Xinjiang,the five Central Asian countries,and Pakistan.

6 Conclusion

The interconnection of power grids in various countries is the general trend of global power development.The synchronous power grids in major countries and regions in the world show a pattern of development from smaller to larger scales with expanding scopes.Under the guidance of the “The Belt and Road” strategic policy,strengthening cooperation with the five Central Asian countries and Pakistan for power construction has broad prospects for development.Firstly,the geographic location adjacent to each country is the “geographical advantage” of multinational cooperation.Secondly,from the perspective of analysis of the three aspects of national policy,power supply and load complementation,and technical feasibility,there have the basic conditions for interconnection between Xinjiang,the five Central Asian countries,and Pakistan.Finally,the interconnection between Xinjiang,the five Central Asian countries,and Pakistan is conducive to the comprehensive utilization of energy in various regions.Additionally,it is conducive to improving the integration capacity of renewable energy in various regions,while simultaneously solving the problem of power shortage in Pakistan.Therefore,effectively utilizing the country’s resources and technological advantages will result in achieving a multi-national win-win situation.

Acknowledgements

This Work was Supported by the State Grid Scientific and Technological Project(Title:Research on the Development and Integration Mode of Renewable Energy in Xinjiang Power Grid under the Background of Multinational Interconnection,NY71-17-008).