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4. Large PV System Jun HAGIHARA Tokyo Electric Power Company – e8 Member. Solar PV Design Implementation O&M March 31- April 11, 2008 Marshall Islands. 4. Large PV system . Contents. 4-1. Grid Connected (Large PV system). 4-1-1. System Configuration 4-1-2. Type of grid connection
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4. Large PV SystemJun HAGIHARATokyo Electric Power Company – e8 Member Solar PV Design Implementation O&M March 31- April 11, 2008 Marshall Islands
4. Large PV system • Contents 4-1. Grid Connected (Large PV system) 4-1-1. System Configuration 4-1-2. Type of grid connection 4-1-3. Examples 4-1-4. Distribution NW 4-1-5. Problems on distributed generation 4-1-6. Guide line on distributed generation 4-1-7. Voltage fluctuation by reverse flow 4-1-8. Voltage fluctuation on disconnection 4-1-9. Islanding operation 4-1-10. Detection of islanding operation 4-1-11. Diversity of grid connected generator
4. Large PV system • Contents 4-2. Grid Connected (Hybrid system) 4-2-1. System Configuration 4-2-2. Examples 4-2-3. New components 4-2-4. Planning & design 4-2-5. Check list on planning 4-2-6. One more resource: Energy conservation
4-1-1. Grid connected: Large PV system: System configuration PV panel Inverter Grid-connected Optional battery PCS For a for village (> 40kW) Optional Battery Grid Delivers the power to the households and common equipments through a grid 24 hours power supply by existing generators
4-1-2. Grid connected: Large PV system: Type of grid connection Grid connection - Low voltage - High voltage • Buy power from grid if load > PV output • Sell power to grid if load < PV output No islanding operation Reverse flow No reverse flow • Anytime load > PV output • Reverse power flow relay Reverse flow • On reverse flow, same as above • With battery system, backup power shall be supplied even in power outage Islanding operation No reverse flow Source: NEDO
4-1-3. Grid connected: Large PV system: Examples (1) Source: KEPCO Installed in 2008 at Funafuti, Tuvalu by E8 (KEPCO) Connected with grid 40kW PV Decrease approx. 50t-Co2/y [100 klbs-Co2/y]
4-1-3. Grid connected: Large PV system:Examples (2) Source: NEDO Installed in 2005 at Beijing, China by NEDO (TEPCO+PVTEC) Office use plus connected with 10kV grid 140kW PV Comparison of various kind of PV modules (crystalline, amorphous)
4-1-3. Grid connected: Large PV system:Examples (2) Source: NEDO
4-1-3. Grid connected: Large PV system:Examples (3) Source: NEDO Installed in 2004-2007 at Ohta, Japan by NEDO (Kandenko et al.) 553 residential houses Total 140kW PV, connected at 100V with 6.6kV distribution line Evaluation of the islanding operation protection
4-1-3. Grid connected: Large PV system:Examples (3) PV Junction box Inverter etc. Load Source: NEDO Installed in 2004-2007 at Ohta, Japan by NEDO (Kandenko et al.) 553 residential houses Total 140kW PV, connected at 100V with 6.6kV distribution line Evaluation of the islanding operation protection
4-1-4. Grid connected: Large PV system:Distribution NW Maintain system voltage and frequency anytime. Grid Generator Load Voltage(V) Balance between • Generation and load • Transmission power and installed capacity Frequency (F)
4-1-4. Grid connected: Large PV system:Distribution NW Maintain system voltage and frequency anytime. Grid Distribution substation Feeder
Distribution substation き線イメージ張りつけ 4-1-4. Grid connected: Large PV system: Distribution NW Maintain system voltage and frequency anytime.
4-1-4. Grid connected: Large PV system: Distribution NW Maintain system voltage and frequency anytime. Load Grid power Reverse power flow from distributed generation Load Load G Load • Power flows from generator to tail end of grid • System size suitable to load size Load
4-1-4. Grid connected: Large PV system: Distribution NW Maintain system voltage and frequency anytime. Hard to keep system voltage Grid Disconnected from grid ↓ Hard to keep system frequency × Distributed generation G Distribution substation Feeder
Light load Heavy load 4-1-4. Grid connected: Large PV system: Distribution NW Maintain feeder voltage Grid High voltage Low voltage Distribution substation Feeder Control voltage at each bank Voltage Proper voltage Distance from substation
4-1-4. Grid connected: Large PV system: Distribution NW Maintain feeder voltage On-load tap-changer at pole transformer Secondary side Primary side Distribution substation High voltage Low voltage Voltage Raise voltage by switching tap-changer Proper voltage Distance from substation
4-1-4. Grid connected: Large PV system: Distribution NW Maintain feeder voltage Distribution substation Control secondary voltage by monitoring current and changing tap of transformer High voltage SVR (Step voltage Regulator) Low voltage Voltage Raise voltage by SVR Proper voltage Distance from substation
Light load Heavy load 4-1-4. Grid connected: Large PV system: Distribution NW Maintain feeder voltage Reverse power flow Distribution substation High voltage Low voltage Distributed Generation Voltage Proper voltage Deviation from proper voltage Distance from substation
4-2-2. Grid connected: Large PV system: Distribution NW Maintain feeder voltage Distribution substation Reverse power flow High voltage Low voltage Can control voltage by monitoring reverse flow from distributed generation, but… Distributed Generation Voltage Light load Heavy load Proper voltage Distance from substation
4-1-4. Grid connected: Large PV system: Distribution NW Maintain feeder voltage Disconnection Distribution substation High voltage Low voltage Distributed Generation Voltage Deviation from proper voltage Proper voltage Light load Heavy load Distance from substation
4-1-4. Grid connected: Large PV system: Distribution NW Earth fault protection of feeder with distributed generation High voltage feeder Generator Without disconnection of distributed generation, earth fault continues even by breaking CB at substation. (Threat of equipment damage and electric shock) Distribution substation It is necessary for distributed generation to be disconnected in concert with the fault detection of system.
4-1-5. Grid connected: Large PV system: Problems on distributed generation On grid connection of distributed generation anarchically, the following problems should be investigated. • Power quality • Possibility of harmful effect to other customers via grid • Become harder to operate grid in maintaining power quality and/or maintenance • Safety/security (injury, equipment damage) • Public safety should be assured especially for distribution line which is easily accessible to public. ・ It is necessary to clarify/establish technical rule necessary to orderly dissemination of distributed generation, safety/security, maintaining of reliability and power quality.
4-1-6. Grid connected: Large PV system: Guide line on distributed generation Guide line on grid connection Electrical system of generator Power factor Protection relay Measures for voltage fluctuation Short circuit capacity Communication tree on emergency
Q P P G G Deviation 4-1-7. Grid connected: Large PV system: Voltage fluctuation by reverse flow • Reactive power control at power receiving end by generator owner • If not effective, use of exclusive line or reinforcing feeder shall be made by the cost of generator owner.
G L G L Disconnection Load increase Deviation in voltage Load shedding Load decrease Maintain voltage Voltage Voltage Maintain voltage Deviation 4-1-8. Grid connected: Large PV system:Voltage fluctuation on disconnection Automatic load shedding shall be implemented by generator owner
① Substation ② ③ CB break ① Crane touches feeder. ② Fault detection, then CB break. ※PV system is running (islanding operation) ③ Threat of electrical shock for worker near crane and public. 4-1-9. Grid connected: Large PV system:Islanding operation
4-1-10. Grid connected: Large PV system:Detection of islanding operation Example of detection method • Active detection • Add disturbance signal from generator to grid continuously • On power outage, detect increased response to disturbance signal • Secure detection, but need several seconds • Passive detection • On power outage, detect phase change of P, Q balance • Possible instant detection • But used as backup of active detection for grid connected generator in high voltage, because of little change at rotating generator → Use multiple detection to detect absolutely
4-1-11. Grid connected: Large PV system: Diversity of grid connected generator High voltage Distribution substation L L L Load Load Load G L G L Transformer Reverse flow (G > L) No reverse flow (G < L) Low voltage L L L Load Load Load G L G L Reverse flow (G > L) No reverse flow (G < L)
4-2-1. Grid connected: Hybrid system: System configuration PV panel Wind Biomass Micro-hydro Inverter Genset (runs for only a few hours per day) PCS For a for village (> 100kW) Optional Grid-connected Optional battery Grid Battery 24 hours power supply by existing generators Delivers the power to the households and common equipments through a grid
4-2-2. Grid connected: Hybrid system: Examples (1) Plant Digestive gas tank Digestive gas supply Separator Scarp wood Gas engine Battery system PV system Sludge digester Steam boiler (existing) Biomass boiler for woody material (1t/h) School C School D School A School B PV system Wind power PV system Wind power Buy power from grid Office B Office A Office C PV system Wind power Grid Source: NEDO Independent line (power & comm.) Total 5.4km
4-2-2. Grid connected: Hybrid system: Examples (1) Power receiving panel Gas engine Woody debris boiler Gas tank Heat/gas pipe Battery system • Installed in 2005 at Hachinohe, Japan by NEDO (Mitsubishi, Hachinohe city) • For schools and city ofiice • Grid connected microgrid • PV: 50kW, 10kW, 2 * 10kW • Wind: 2 * 2kW, 2 * 8kW • Gas engine: 3 * 170kW • Battery system: 1,440kWh • Woody debris boiler: 1.0t/h [2.0klbs/h] • Digestion gas boiler: 4.2t/h [8.4klbs/h] Source: NEDO
4-2-2. Grid connected: Hybrid system: Examples (1) GE1 + GE2 GE1 Battery PV + Wind Power flow at PCC Demand Control error Energy in battery Energy in battery (right axis) GE1 + GE2 Load GE1 PV + Wind Power flow at PCC (power purchased) : pink Control error (difference from plan) : red Battery Source: NEDO
4-2-2. Grid connected: Hybrid system: Examples (2) : PV+BESS High Quality Power Supply To use PV widely To improve Power Quality (PQ) Utilization of RE Voltage dip High Quality Power Supply Peak Shaving PS + PQ PV BESS Effective use of PV Problems of PV - Sudden output change - Voltage and frequency fluctuation PV Output Stabilization With BESS PV output Without BESS Time Time
4-2-2. Grid connected: Hybrid system: Examples (2) : PV+BESS High Quality Power Supply PV 80kW Max Use Interruption Dip AC433V 力 力 High Speed SW Normal: closed Abnormal: Opened TR Grid On Voltage sag,power is supplied by battery. Hi-Tech Farm DC 480V Critical Load Battery 2000Ah PCS 375kVA (Power Conversion System) Mitigate • Voltage Fluctuation • Voltage dip • Momentum interruption • Load Leveling BESS
4-2-2. Grid connected: Hybrid system: Examples (2) : PV+BESS High Quality Power Supply PCS (375kVA) - High speed switching - No power interruption Advanced Battery System Cycle-use Lead Acid Battery - Load leveling (100kW, 2.5hr) - PQ protection - EPS (240kW, 10min) PV (80kW) - Roof for parking lot - On rooftop of canteen building Remark: Shown equip. capacity is present targeted value. It will be finalized in detail design stage.
4-2-2. Grid connected: Hybrid system: Examples (2) : PV+BESS High Quality Power Supply New s/s building for battery and elec. equip. PV 70kW Office Parking PV 10kW
4-2-3. Grid connected: Hybrid system: New components • NAS battery • Developed by TEPCO and NGK Insulators Ltd. • Cycle-use battery • Suitable for load leveling Installed underground of an amusement park, Tokyo Dome City LaQua. - Peak shaving - Backup power (10%-720kWh) for selected loads Safety Tube Sodium Flow Path Beta Alumina Electrolyte Fuse Cell Packed Sand Vacuum Thermal Enclosure (upper) Sodium Electrode Sulfur Electrode Safety tube Beta alumina Electrolyte Main Pole Cell Case Side Heater Vacuum Thermal Enclosure (lower) 50 kW MODULE CELL
4-2-3. Grid connected: Hybrid system: New components • Shin-Kobe Electric Machinery, Co., Ltd • Cycle-use lead acid battery • Stationary VRLA batteries for power storage (LL 1500) • Suitable for load leveling • 1050Ah (25 degree C, 0.23C) • 3,000 cycle (70%DOD) • 10 years lifetime Source: Shin-Kobe Electric Machinery
4-2-3. Grid connected: Hybrid system: New components • Kawasaki Heavy Industry • Nickel hydrogen battery • Environment Friendliness (No usage of rare or hazardous material) • Suitable for load leveling Source: Kawasaki Heavy Industries
4-2-3. Grid connected: Hybrid system: New components • Power systems Co. Ltd. • Wellgeo series • EDLC (Electrical Double Layer Capacitor) Source: Power systems Co. Ltd.
4-2-3. Grid connected: Hybrid system: New components CIGS type - electrode Buffer CIGS + electrode + electrode Si monocrystal type electrode N Si P Si + electrode • Advanced PV module • CIS/CIGS (cupper-indium-gallium- serene) • Thin-film PV (4 micro-meter [1.47 * 10-4 inch]) • 125W • Developed by Honda Source: Honda Soltec
4-2-4. Grid connected: Hybrid system:Planning & design System, equip. spec., supplier, capacity, supply characteristics, reliability, cost and so on. • Same as shown in before • Economic efficiency is important. • Compare generating cost with electricity charge. • Investigate optimal (economical) operational pattern Survey of various REN Concept design of the system Demand characteristics, energy cost, electricity tariff REN main unit, inverter, grid connection, battery, env. measure Investigation of target site Determination of equipment spec. Estimate supplied power and energy Estimate project cost Determine operation pattern Estimate maintenance cost Estimate total running cost Analyze cost/benefit Effect on environmental protection Generation cost, distribution cost, cash flow Effect on energy conservation Implementation
4-2-5. Grid connected: Hybrid system: Check list on planning (1) • Concept and purpose • For what? • Purposed should be shared among concerned parties. • Where? • In existing facility or not? Exact location. • What load? • Characteristics and size of load. Enough space for installed equipment? • Which system? • Isolated or grid-connected? With battery or not? • When and how much? • Construction schedule and cost. Can it be available? Same as shown in before Economic efficiency is important. Compare generating cost with electricity charge. Investigate optimal (economical) operational pattern
4-2-6. Grid connected: Hybrid system: One more resource: Energy conservation • Submit periodical reports on the use of energy • Prepare and submit mid- and long-term plans for measures to achieve energy conservation targets • Appoint energy managers Energy management at factory (Japanese case) Factories/business establishments with high energy consumption(Type 1 Designated Energy Management Factories) Factories/business establishments with medium energy consumption (Type 2 Designated Energy Management Factories) Annual fuel (thermal) use: 3000 kl [679 kilogallon] in crude oil equivalent or larger Annual electricity use: 12 million kwh or larger Annual fuel (thermal) use: 1500 kl [339 kilogallon] in crude oil equivalent or larger Annual electricity use: 6 million kwh or larger Factories and business establishments Business Establishments Factories Measures Measures Measures • Appointment of a qualified person for energy management of type 2 designated factory • Preparation & Submission of Periodical Reports • Appointment of Energy Manager (Mandatory to possess a license for a qualified person for energy management of type 1 designated factory) • Preparation & Submission of Periodical Reports • Formulation & Submission of Mid- and long-term Plans • Appointment of a qualified person for energy management of type 2 designated factory (Training Required) • Preparation & Submission of Periodical Reports • Preparation and Submission of mid- and long-term plans (Participation by a qualified person required) Business Establishments Factories Department Store Schools Office Building Hotel Source: ECCJ 22
Improving Equipment Efficiency (Japanese case) 4-2-6. Grid connected: Hybrid system: One more resource: Energy conservation *Top Runner Program: The concept of the program is that fuel economy standards for vehicles and energy conservation standards for electric appliances, etc. shall be set exactly the same as or higher than the best standard value of each product item currently available in the market. Example of Top Runner Program Fuel Economy (km/ ) Energy conservation standard based on the Top Runner Program Source: ECCJ 26 Energy conservation effect in comparison with FY2000 (against FY1999 figures for transformers)
Energy-Saving Labeling System (Japanese case) 4-2-6. Grid connected: Hybrid system: One more resource: Energy conservation • Inform consumers of energy efficiency of home appliances • Promote energy-efficient products. Examples of energy-saving labeling Energy conservation standard achievement percentage Energy consumption efficiency Target year FY2005 Energy conservation standard achievement percentage Energy consumption efficiency Target year FY2005 Label for the product's main unit As of April 2005, labeling is applied to the following 13 products: air conditioners, refrigerators, freezers, fluorescent lights, TV sets, space heaters, gas cooking appliances, gas water heaters, oil water heaters, electric toilet seats, computers, magnetic disks, and transformers. Source: ECCJ 27
Energy-Saving Labeling System (Japanese case) 4-2-6. Grid connected: Hybrid system: One more resource: Energy conservation Expected Annual Electricity Bill Labeling to be indicated Achievement Rate Evaluation APF (Annual Energy Efficiency): Key Factor for Labeling Total Consumption in a year (kWh) Label Color Model Number Heating Cooling Manufacture Name of Product Ranking Average COP in Both Cooling and Heating Consumption in Cooling Period (kWh) COP Power Consumption (W) Max. Ave. Min. Class name: Cooling Capacity 3.6 kW and Free Dimension