A kind of micro-grid system method for designing
Technical field
The present invention relates to electric power system design method, be specifically related to a kind of micro-grid system method for designing.The method is for the construction of micro-capacitance sensor.
Background technology
Along with the requirement of the increasingly exhausted of traditional fossil energy and low-carbon (LC), environmental protection, the distributed power generation of clean energy resource has become current research focus, but distributed power source direct grid-connected likely causes the problems such as the quality of power supply, power grid security and stability of electric power system.In order to improve the flexibility of power system operation, controllability and economy further, and meet the requirements at the higher level of power consumer to the quality of power supply and power supply reliability better, the concept of micro-capacitance sensor is arisen at the historic moment.
Micro-grid system is the distributed power source network that a kind of independence is very strong; combined as required by energy storage device groups such as photovoltaic generation, wind power generation, fuel gas generation or diesel generation, fuel cell and storage batterys; the device such as access control, protection and metering, forms an area autonomy system again.Micro-capacitance sensor technology is intended to flexible, the efficient application that Distribution network aspect realizes distributed generation technology, solution substantial amounts, various informative distributed power source are incorporated into the power networks, and by Intelligent Energy management holding power local optimum and balance, effective reduction system cloud gray model scheduling difficulty, micro-capacitance sensor independent operating also can continue when outside electric network fault to power to critical load, improves electricity consumption reliability.Micro-capacitance sensor technology is one of key technology realizing distributed generation system extensive use.
China's seashore line length, island quantity is many, wherein is no lack of the island that distance seashore is far away, restrict by geographic factor, each island electrical network network with continental Grid, is difficult to ensure power supply reliability, and current island main dependence diesel engine unit of powering is powered, not only there is problem of environmental pollution, and electricity price is higher.For present situation, micro-capacitance sensor is built on island, utilizing clean regenerative resource to power to load on island is solve the most effective mode of island electrical problem.In addition, in remote mountain areas, plateau, large enterprise, the multiple occasion such as city intelligent community can by micro-capacitance sensor for user provides clean, reliable electric energy.But also there is following problem in the construction at present for micro-capacitance sensor:
1) existing micro-capacitance sensor is Scientific Research Service, there is many experimental equipments, do not consider practical application request;
2) existing micro-capacitance sensor lacks Techno-Economic Analysis;
3) not there is engineering promotional value;
4) capacity for distributed power source various in micro-capacitance sensor is determined often rule of thumb to choose, and the cost of whole system is higher, and equipment component cannot make full use of;
5) complete micro-capacitance sensor rack and distributed power source design is not had.
In sum, also there is certain distance in routine work life micro-capacitance sensor being applied to people.
Summary of the invention
Object of the present invention, being also there is no the deficiencies such as complete micro-capacitance sensor rack and distributed power source design to overcome prior art, a kind of micro-grid system method for designing being provided, the construction of micro-capacitance sensor can be instructed by the method, reduce the construction cost of micro-capacitance sensor, layout of making rational planning for.
Object of the present invention can be achieved through the following technical solutions:
A kind of micro-grid system method for designing, is characterized in that: comprise distributed power source scheme in design micro-capacitance sensor access power distribution network scheme, design micro-capacitance sensor network instruction plan and design micro-capacitance sensor;
1) micro-capacitance sensor access power distribution network scheme is designed
First whether access power distribution network according to micro-capacitance sensor and determine lonely net pattern or grid-connect mode, when selecting lonely net pattern, micro-capacitance sensor independent operating; When selecting grid-connect mode, adopt alternating-current direct to connect in succession, connect through current source converter (csc) CSC or access power distribution network through voltage source converter VSC; Then determine according to micro-capacitance sensor amount of capacity electric pressure and the on-position of accessing power distribution network;
2) micro-capacitance sensor network instruction plan is designed
According to bus character, micro-capacitance sensor is divided into interchange micro-capacitance sensor, direct-current grid and alternating current-direct current mixing micro-capacitance sensor three kinds, its supply power mode is selected to be that dual power supply is powered or single power supply according to the load level of user, that low pressure micro-capacitance sensor or middle pressure micro-capacitance sensor select its mode of connection according to micro-capacitance sensor, described middle pressure micro-capacitance sensor is divided into some sub-micro-capacitance sensor, and adopts overhead transmission line network connection to mix with cable line network connection to coordinate;
3) distributed power source scheme in micro-capacitance sensor is designed
Select the type of distributed power source, under the prerequisite meeting micro-capacitance sensor safety and stability and the quality of power supply, preferentially select renewable energy power generation form, and be equipped with the energy storage device corresponding to described renewable energy power generation; Select the capacity of distributed power source, determine according to micro-grid system supply and demand present situation, load growth prediction and plan for land project development condition, and ensure the reliable power supply of firsts and seconds load when micro-capacitance sensor isolated power grid.
Further scheme of the present invention: described grid-connect mode refers to micro-capacitance sensor and the electrical network paired running of being powered by large-sized unit, namely exists on major loop with described power distribution network of being powered by large-sized unit and is electrically connected; Micro-grid connection is run to be divided into according to Power Exchange mode and commonly grid-connectedly and grid-connected is not surfed the Net two kinds, common grid-connected middle micro-capacitance sensor carries surplus power to electrical network, grid-connected do not surf the Net in the power of micro-capacitance sensor unit do not send outside, namely points of common connection PCC place power flow direction only flows to micro-capacitance sensor user from the electrical network of being powered by large-sized unit.
Further scheme of the present invention: determine according to micro-capacitance sensor amount of capacity the electric pressure accessing power distribution network described in design micro-capacitance sensor access power distribution network scheme, refer to: the micro-capacitance sensor access 380V power distribution network of below 200kW, the micro-capacitance sensor access l0kV power distribution network of 200 ~ 6000kW or the power distribution network of below l0kV, capacity is greater than micro-capacitance sensor access more than the l0kV power distribution network of 6000kW or determines the electric pressure of access by setting capacity; The position of micro-capacitance sensor access power distribution network, the micro-capacitance sensor of below 200kW directly accesses 380V distribution feeder nearby, and 200kW and above micro-capacitance sensor need the high-voltage distribution network accessing more than l0kV, and on-position comprises transformer station high-pressure side, low-pressure side.
Further scheme of the present invention: during the position of the high-voltage distribution network of described micro-capacitance sensor access more than l0kV, meet following condition: 1. can effective Change Power and the safe and stable operation of electrical network can be guaranteed; 2. when points of common connection PCC place is incorporated to more than one power supply, totally should consider the impact of power supply, in micro-capacitance sensor, power supply total capacity is in principle no more than 25% of peak load in upper level transformer-supplied region; 3. in micro-capacitance sensor, the short circuit current of power grid point is more than or equal to 10 with the ratio of micro-capacitance sensor source nominal electric current.
Further scheme of the present invention: described interchange micro-capacitance sensor refers to that each distributed power source and load access common ac bus, and DC power supply is accessed by inverter, communication electricity consumption DC load by commutation system from AC system power taking; Described direct-current grid refers to that micro-grid system is based on a DC bus construction, and be connected with AC power by a unified inverter, the AC load in system is connected with DC bus by inversion or rectifying installation with power supply; Described alternating current-direct current mixing micro-capacitance sensor refer to various micro power and bus type of attachment various, usually there will be two buses, an ac bus, a DC bus, each distributed power source and load access bus mode are chosen by its type and are exchanged or direct current mode.
Further scheme of the present invention: the load level of described user is divided into first order load user, two stage load users and three stage load users, the user of first order load and two stage loads is powered by dual power supply; The load of particular importance in first order load is powered, except being powered by dual power supply, also sets up independently emergency power supply; Single power supply is adopted to the user of three stage loads; For asymmetric load user, when three-phase electricity consumption unsymmetrical current exceedes 10% of power supply unit rated current, high voltage order one is adopted to power.
Further scheme of the present invention: described low pressure micro-capacitance sensor refers to that radius of electricity supply is no more than 400m, and load is concentrated, the electrical network that network configuration is fairly simple, adopts cable wiring; Described middle pressure micro-capacitance sensor is comparatively large because of radius of electricity supply, be then divided into the sub-micro-capacitance sensor (service area) that several are relatively independent;
Described every sub-micro-capacitance sensor is can the standard of isolated power grid divide, internal electric source and the balance of load and the power supply reliability of important load when namely considering sub-micro-capacitance sensor isolated power grid, every sub-micro-capacitance sensor has clear and definite supply district, be not overlapping, and can adjust according to the development of load in good time and optimize; Sub-micro-capacitance sensor inside can divide as required again, forms multistage micro-capacitance sensor.
Further scheme of the present invention: the 10kV circuit in middle pressure micro-capacitance sensor meets the requirement of terminal voltage quality, is divided three classes by radius of electricity supply: category-A service area 1.5km, category-B service area 2.5km, C class service area 4.0km; The method of overhead transmission line network connection: the mode of connection of " three segmentations three are got in touch with " is adopted for A, category-B service area, waypoint arrange according to network connection and the corresponding variation of load variations; C class service area is adopted to the connection of ring power network mode of open loop operation, when the initial stage, load was less, adopt the single supply trunk formula mode of connection, and along with load growth is progressively to the transition of connection of ring power network mode; The method of cable line network connection: 1. when single loop feeder load electric current is less than or equal to 50% of its safe carrying capacity, by " 2-1 " Single-ring network wiring that two feedback line compositions are for subsequent use each other; 2. when single feedback line load current is greater than 50% of its safe carrying capacity, three feedback line can form " 3-1 " Single-ring network wiring for subsequent use each other, the load current of every feedback line cable is determined according to actual conditions, and maximum load electric current is no more than 2/3 of cable security ampacity; 3. in high load capacity City Regions, the wiring of feeder cable composition " N for standby ", comprises " two is standby for one ", " three is standby for one " and " four is standby for one ", cable in stock circuit not on-load under normal operating mode; 4. in category-A service area, when power supply reliability requires very high, the mode of connection of dual-ring network is made up of four telegram in reply cable feeder lines.
Further scheme of the present invention: the type of described selection distributed power source also considers following factor,
1. according to actual conditions configuration diesel engine generator or miniature gas turbine;
2. according to the wind energy in project location district, solar energy resources, micro-grid system supply and demand present situation, load growth prediction, wind, light generating on impact and the requirement of system, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the construction feasibility that wind, light generate electricity; Abundant at wind energy resources, stable, wind power concentration grade is at least the region consideration wind power generation of 2 grades; Abundant at solar energy resources, stable, global solar radiation aboundresources intensity grade is at least the region consideration construction photovoltaic generation of 4 grades;
3. the type of energy storage device is selected according to the function of energy storage in micro-capacitance sensor, when for peak valley adjustment, system reserve, less demanding to response speed time, the energy storage type selecting energy density large; When for system power quality quick adjustment, select that instantaneous power is large, the energy storage type of fast response time;
4. the micro-capacitance sensor of isolated power grid, or there is the micro-capacitance sensor of I and II load, the distributed power source with stable power-supplying ability and well-tuned performance need be configured, and distributed power source is arranged near important load.
Further scheme of the present invention: the capacity of described selection distributed power source also considers following factor:
1. the distributed power source total capacity guaranteeing to have stable power-supplying ability is greater than the total capacity of firsts and seconds load in microgrid, and according to load growth in 5 years prediction consideration 15% allowance.
2. according to the wind energy resources in project location district, micro-grid system supply and demand present situation, load growth prediction, wind power generation on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of wind power generation, be no more than 25% of the peak load in upper level transformer-supplied region in principle by the wind power generation total capacity of 380V electric pressure access micro-capacitance sensor, control in 30% of accessed micro-capacitance sensor circuit maximum delivery capacity by the wind power generation total capacity of 10kV electric pressure access micro-capacitance sensor;
3. according to the manufacture level of wind turbine generator, technology maturation degree and price, draft some different single-machine capacity schemes, the wind regime feature of integration project, the mounting condition of Wind turbines and equipment conveying condition, determine single-machine capacity scope;
4. according to the solar energy resources in project location district, micro-grid system supply and demand present situation, load growth prediction, photovoltaic generation on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of photovoltaic generation; Be no more than 25% of the peak load in upper level transformer-supplied region in principle by the photovoltaic generation total capacity of 380V electric pressure access micro-capacitance sensor, control in 30% of accessed micro-capacitance sensor circuit maximum delivery capacity by the photovoltaic generation total capacity of 10kV electric pressure access micro-capacitance sensor;
5. according to micro-grid system supply and demand present situation, load growth prediction, energy storage device on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of energy storage device, when energy storage device is as system reserve, preparation time was determined according to the time of restoring electricity after micro-capacitance sensor accident interruption.
Beneficial effect of the present invention:
1) the invention provides the design of distributed power source in micro-capacitance sensor the access design of power distribution network, the design of micro-capacitance sensor network configuration and micro-capacitance sensor, thus instruct the construction of micro-grid system, for the construction of micro-grid system provides foundation, and improve design efficiency and the fail safe of micro-grid system.
2) the present invention is actual demand according to user and the micro-grid system that designs, and practical, programming and distribution are reasonable, also reduce the construction cost of micro-grid system.The micro-grid system of construction of the present invention achieves as daily life work provides the object of service.
Embodiment:
The present invention is further illustrated below.
A kind of micro-grid system method for designing, comprises distributed power source design in micro-capacitance sensor access Distribution system design scheme, micro-capacitance sensor network configuration design and micro-capacitance sensor;
1) micro-capacitance sensor access power distribution network scheme is designed
First whether access power distribution network according to micro-capacitance sensor and determine lonely net pattern or grid-connect mode, when selecting lonely net pattern, micro-capacitance sensor independent operating; When selecting grid-connect mode, adopt alternating-current direct to connect in succession, connect through current source converter (csc) CSC or access power distribution network through voltage source converter VSC; Then determine according to micro-capacitance sensor amount of capacity electric pressure and the on-position of accessing power distribution network.
Described lonely net pattern refers to micro-capacitance sensor independent operating, is not connected with bulk power grid, by power-balance and the stable operation of control realization therein;
Described grid-connect mode refers to micro-capacitance sensor and the electrical network paired running of being powered by large-sized unit, namely exists on major loop with regular distribution net and is electrically connected; Micro-grid connection is run can be divided into according to Power Exchange mode and commonly grid-connectedly and grid-connected is not surfed the Net two kinds, common grid-connected micro-capacitance sensor can carry surplus power to electrical network, grid-connected micro-capacitance sensor of not surfing the Net then strictly forbids that the power of micro-capacitance sensor unit is sent outside, and namely points of common connection (PCC) place power flow direction can only flow to micro-capacitance sensor user from electrical network.Grid-connect mode can be subdivided into again grid-connected online pattern and grid-connected pattern of not surfing the Net.
The described electric pressure determining access power distribution network according to micro-capacitance sensor amount of capacity, refer to: the micro-capacitance sensor access 380V power distribution network of below 200kW, the micro-capacitance sensor access l0kV power distribution network of 200 ~ 6000kW or the power distribution network of below l0kV, capacity is greater than micro-capacitance sensor access more than the l0kV power distribution network of 6000kW or determines the electric pressure of access by setting capacity.
The position of micro-capacitance sensor access power distribution network, the micro-capacitance sensor of below 200kW directly accesses 380V distribution feeder nearby, and 200kW and above micro-capacitance sensor need the high-voltage distribution network accessing more than l0kV, and on-position comprises transformer station high-pressure side, low-pressure side.
During the position of the high-voltage distribution network of described micro-capacitance sensor access more than 10kV, meet following condition: 1. can effective Change Power and the safe and stable operation of electrical network can be guaranteed; 2. when points of common connection PCC place is incorporated to more than one power supply, totally should consider the impact of power supply, in micro-capacitance sensor, power supply total capacity is in principle no more than 25% of peak load in upper level transformer-supplied region; 3. in micro-capacitance sensor, the short circuit current of power grid point is more than or equal to 10 with the ratio of micro-capacitance sensor source nominal electric current.
2) micro-capacitance sensor network configuration design is designed
According to bus character, micro-capacitance sensor is divided into interchange micro-capacitance sensor, direct-current grid and alternating current-direct current mixing micro-capacitance sensor three kinds, its supply power mode is selected to be that dual power supply is powered or single power supply according to the load level of user, that low pressure micro-capacitance sensor or middle pressure micro-capacitance sensor select its mode of connection according to micro-capacitance sensor, described middle pressure micro-capacitance sensor is divided into some sub-micro-capacitance sensor, and adopts overhead transmission line network connection to mix with cable line network connection to coordinate.
Exchange micro-capacitance sensor and refer to that each distributed power source and load access common ac bus, DC power supply is accessed by inverter, and DC power supply comprises: photovoltaic, energy storage etc., the DC load of communication electricity consumption etc. by commutation system from AC system power taking.Direct-current grid refers to that micro-grid system is based on a DC bus construction, and be connected with AC power by a unified inverter, the AC load in system is connected with DC bus by inversion or rectifying installation with power supply.Alternating current-direct current mixing micro-capacitance sensor refer to various micro power and bus type of attachment various, usually there will be two buses, an ac bus, a DC bus, each distributed power source and load access bus mode are chosen by its type and are exchanged or direct current mode.
The load level of described user is divided into first order load user, two stage load users and three stage load users, and the user of first order load and two stage loads is powered by dual power supply, when a power failure, is damaged when another power supply is different; The load of particular importance in first order load is powered, except being powered by dual power supply, also sets up independently emergency power supply; Single power supply is adopted to the user of three stage loads; For asymmetric load user, when three-phase electricity consumption unsymmetrical current exceedes 10% of power supply unit rated current, high voltage order one is adopted to power.
Described low pressure micro-capacitance sensor refers to that radius of electricity supply is no more than 400m, and load is concentrated, the electrical network that network configuration is fairly simple, adopts cable wiring; Described middle pressure micro-capacitance sensor is comparatively large because of radius of electricity supply, be then divided into the sub-micro-capacitance sensor (service area) that several are relatively independent; Described every sub-micro-capacitance sensor is can the standard of isolated power grid divide, internal electric source and the balance of load and the power supply reliability of important load when namely considering sub-micro-capacitance sensor isolated power grid, every sub-micro-capacitance sensor has clear and definite supply district, be not overlapping, and can adjust according to the development of load in good time and optimize; Sub-micro-capacitance sensor inside can divide as required again, forms multistage micro-capacitance sensor.
10kV circuit in middle pressure micro-capacitance sensor meets the requirement of terminal voltage quality, is divided three classes by radius of electricity supply: category-A service area 1.5km, category-B service area 2.5km, C class service area 4.0km;
The method of overhead transmission line network connection: the mode of connection of " three segmentations three are got in touch with " is adopted for A, category-B service area, waypoint arrange according to network connection and the corresponding variation of load variations; C class service area is adopted to the connection of ring power network mode of open loop operation, when the initial stage, load was less, adopt the single supply trunk formula mode of connection, and along with load growth is progressively to the transition of connection of ring power network mode.
The method of cable line network connection: 1. when single loop feeder load electric current is less than or equal to 50% of its safe carrying capacity, by " 2-1 " Single-ring network wiring that two feedback line compositions are for subsequent use each other; 2. when single feedback line load current is greater than 50% of its safe carrying capacity, three feedback line can form " 3-1 " Single-ring network wiring for subsequent use each other, the load current of every feedback line cable is determined according to actual conditions, and maximum load electric current is no more than 2/3 of cable security ampacity; 3. in high load capacity City Regions, the wiring of feeder cable composition " N for standby ", comprises " two is standby for one ", " three is standby for one " and " four is standby for one ", cable in stock circuit not on-load under normal operating mode; 4. in category-A service area, when power supply reliability requires very high, the mode of connection of dual-ring network is made up of four telegram in reply cable feeder lines.
3) distributed power source scheme in micro-capacitance sensor is designed
Select the type of distributed power source, under the prerequisite meeting micro-capacitance sensor safety and stability and the quality of power supply, preferentially select renewable energy power generation form, regenerative resource refers to wind power generation, photovoltaic generation etc., and is equipped with the energy storage device corresponding to described renewable energy power generation;
The type of described selection distributed power source also considers following factor:
1. according to actual conditions also configurable diesel engine generator or miniature gas turbine;
2. according to the wind energy in project location district, solar energy resources, micro-grid system supply and demand present situation, load growth prediction, wind, light generating on the impact of system and requirement, on project development conditions such as the impact of engineering cost of electricity-generating and plans for land, prove and determine the construction feasibility that wind, light generate electricity;
Abundant at wind energy resources, stable, wind power generation can be considered in the region that wind power concentration grade is at least 2 grades;
Abundant at solar energy resources, stable, the region that global solar radiation aboundresources intensity grade is at least 4 grades can be considered to build photovoltaic generation;
3. the type of energy storage device is selected according to the function of energy storage in micro-capacitance sensor, when for peak valley adjustment, system reserve, less demanding to response speed time, the energy storage type selecting energy density large; When for system power quality quick adjustment, select that instantaneous power is large, the energy storage type of fast response time;
4. the micro-capacitance sensor of isolated power grid, or there is the micro-capacitance sensor of I and II load, need configure the distributed power source that diesel engine generator, miniature gas turbine or energy storage device etc. have stable power-supplying ability and well-tuned performance, and distributed power source is arranged near important load.
Select the capacity of distributed power source, determine according to micro-grid system supply and demand present situation, load growth prediction and plan for land project development condition, and ensure the reliable power supply of firsts and seconds load when micro-capacitance sensor isolated power grid.The capacity of described selection distributed power source also considers following factor:
1. guarantee that distributed power source total capacity that diesel engine generator, miniature gas turbine or energy storage device etc. have a stable power-supplying ability is greater than the total capacity of firsts and seconds load in microgrid, and according to load growth in 5 years prediction consideration 15% allowance.
2. according to the wind energy resources in project location district, micro-grid system supply and demand present situation, load growth prediction, wind power generation on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of wind power generation, be no more than 25% of the peak load in upper level transformer-supplied region in principle by the wind power generation total capacity of 380V electric pressure access micro-capacitance sensor, control in 30% of accessed micro-capacitance sensor circuit maximum delivery capacity by the wind power generation total capacity of 10kV electric pressure access micro-capacitance sensor;
3. according to the manufacture level of wind turbine generator, technology maturation degree and price, draft some different single-machine capacity schemes, the wind regime feature of integration project, the mounting condition of Wind turbines and equipment conveying condition, determine single-machine capacity scope;
4. according to the solar energy resources in project location district, micro-grid system supply and demand present situation, load growth prediction, photovoltaic generation on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of photovoltaic generation; Be no more than 25% of the peak load in upper level transformer-supplied region in principle by the photovoltaic generation total capacity of 380V electric pressure access micro-capacitance sensor, control in 30% of accessed micro-capacitance sensor circuit maximum delivery capacity by the photovoltaic generation total capacity of 10kV electric pressure access micro-capacitance sensor;
5. according to micro-grid system supply and demand present situation, load growth prediction, energy storage device on the impact of system and requirement, on the impact of engineering cost of electricity-generating and the project development condition of plan for land, prove and determine the capacity of energy storage device, when energy storage device is as system reserve, preparation time was determined according to the time of restoring electricity after micro-capacitance sensor accident interruption.