Coordinated and Optimized Control of Distributed Generation Integration

Coordinated and Optimized Control of Distributed Generation Integration Hui Yu & Wenpeng Luan China Electric Power Research Institute July, 2015

1 Background and introduction 2 Coordinated control of distributed generation resource 3 Implementation examples 4 Summary

Global RE Development Plan EU USA China Japan By 2020: By 2025: By 2020: By 2050: 20% energy efficiency improvement 20% greenhouse gas emission reduction 20% RE share 25% RE share By 2030: 20% wind power generation share Planned wind power 200GW non-fossil energy accounts for 15% of primary energy consumption CO 2 emission per unit of GDP reduced by 40-45% than in 2005 50% RE share 80% greenhouse gas emission reduction by increasing energy efficiency and developing RE Renewable Energy will play an important role in future s electricity supply.

At or near the customer site Operation mode Generation mainly for self use Surplus can be sold to the grid Solar, wind, biomass, geo-thermal, hydro, gas and comprehensive use of multi-types energy

New Challenges in DG Deployment and Power System Operation DG is: Uncertain Partially unpredictable Unstable 5

Technical solution: consider the DG and local load as a small system (i.e. microgrid) From to Distributed integration Independent individual uncontrollable power source Multiple connection points with local grid Group integration Controllable load/power source Single connection point with local grid 6

Technical Solution:Microgrid To the main grid PCC EV Main grid Operations Acted as a controllable Microgrid Operations Heat CHP power resource/load from the main grid perspective Operate in grid integrated/ PV Markets islanded mode Wind Storage Service Provider 7

2 Coordinated control of the DGs Master-slave control of multiple DGs: one DG acts as master Synchronous Signal Measurement for Power Network Main Controller Grid-connected P/Q Control V/F Control Island DG Acts as Master DC AC Distribution Network V,I Measurement V,I Measurement V,I Measurement V,I Measurement Power Electronic Interface PQ Controller Power Electronic Interface PQ Controller Load Controller DG 1 DG n 8

2 Coordinated control of the DGs Peer-to-peer control of multiple DGs Distribution Network PCC V,I Measurement Droop Controller1 f 0 V 0 V,I Measurement U 1 AC DC DG 1 Local Load 1 Power Calculation and Decoupling P P-f&Q-V Droop Control Q f V Droop Controller2 Three Phase Voltage Calculation U 2 AC DC DG 2 Local Load 2 Droop Controller n f 0 V 0 V,I Measurement U n AC DC DG n Local Load n Public Load f 0 V 0 9

2 Coordinated Control of the DGs Coordinated control strategy Based on hierarchical control and energy management Could be 2 or 3 layers (3 layers structure) composed of local control, centralized control, distribution dispatching layer Comparatively mature tech. Maintaining the stable operation of microgrid Realizing the maximum utilization of REs, and the economic objectives of microgrid Integrating the microgrid into the unified dispatching of distribution network via information exchange with distribution network Requiring reliable communication and comparatively large investment Based on multi-proxy tech. Composed of three proxies: component, microgrid and distribution network level proxy Using the self-governing, reaction ability and spontaneous behavior of proxy to decentralize the complex integral control Reduce the complexity of centralized control model, avoid large scale calculation and realize real-time control Fast response to the change of partial grid and reduce the workload of power quality regulation Current research and application mostly focus on the coordination of market transaction and economic of system operation, lacking deep research on the voltage and frequency control

2 Coordinated Control of the DGs Coordinated control strategy based on hierarchical control and energy management 配 Dispatching 网 调 度 层 Layer Distribution 配 电 网 Network Centralized 集 Control 中 控 制 Layer 层 微 网 能 MG 量 EMS 管 理 系 统 微 网 MG 集 中 Central 控 制 器 Controller 微 Point 网 PCC of MG Connection Local 就 Control 地 控 制 层 Layer Inverter 逆 变 器 Protection and 测 控 保 护 装 置 Monitoring Device 断 Circuit 路 器 Breaker Wind 风 Power 力 发 电 光 伏 PV发 电 Storage 储 Battery 能 电 池 Power Quality 电 Improving 能 质 量 治 Device 理 装 置 Load 负 荷 微 Protection 电 网 并 网 at Point 点 保 of 护 MG Connection 电 Power 力 传 Transmission 输 线 路 Line 微 Communication 网 通 讯 线 路 Line

2 Coordinated Control of the DGs Coordinated control strategy based on hierarchical control and energy management Dispatching layer Pass the electric information inside microgrid to distribution network dispatching center, and deliver the dispatching order to microgrid, making the microgrid part of the distribution dispatching by realizing power exchange between microgrid and distribution network through connecting line. Microgrid centralized control layer Collect the condition data of microgrid operation Send dispatching and switch order to local controller Realize system local monitoring via IPC Forward parameter modify order Realize transformation between different communication protocols of upper and lower layer Local control layer of Micro power source/storage/load Upload the operation condition data of micro power source, energy storage, load and equipment of control, protection, testing and metering, to microgrid central controller Realize control of bottom layer equipment according to orders send by microgrid central controller

2 Coordinated control of the DGs Multiple time-scale based optimal energy management strategy Dispatching Center of Distribution 配 电 网 调 Network 度 中 心 Telemetry Data Data Collection Wind/PV/Load Super Short-term Forecast Real-time Storage SOC Tie-line Power Constraint Wind/PV/Load Short-term Forecast Multi-objective Optimization Constraint Short-term 短 期 scheme 计 划 Modify the Scheme Super Short-term Scheme Send the Order Micro Power Sources and Energy Real-time Dispatching MG Energy Management Master Station MG Central Controler Send the Real-time Dispatching Order Micro Power Sources/Storage /Load Controller Short-term scheme Formulate the next storage charge/discharge and micro power source control scheme to realize optimal control, according to the next day PV/wind power and load forecast Super short-term scheme Modify the short-term operation control scheme of micro power source and load according to the super short-term forecast and the real-time storage SOC Real-time dispatching Execute the micro power source and energy real-time dispatching strategy, and send real time dispatching order to relevant controller

3 Microgrid Projects in China China microgrid projects status By the end of 2013, 15 microgrid projects were constructed/under construction 30 microgrid projects will be completed by the end of 2015 (planning installed capacity of 150MW) 14

3 Microgrid Projects in China Characteristics To the main grid 1 Power source: mainly wind power and PV PCC EV Main grid Operations 2 Voltage: 380V: 11 projects (71%) 10kV: 4 projects(29%) Microgrid Operations Heat CHP 3 Installed capacity: 11<=1MW, 4 <=5MW PV Markets 4 Energy storage: 14 deployed ESS 5 Operation method: integrated operation and islanding operation Storage Wind Service Provider 15 P15

3 Implementation Example Microgrid project in east Inner Mongolia Voltage level: 380V Capacity: PV 110kW; Wind power 50kW; lithium battery 42kW/50kWh To provide power supply for 100 households farmers and diary farm, and test power supply in remote rural area via microgrid 16

3 Implementation Example Microgrid project in east Inner Mongolia Site condition and demand analysis Grid condition:35kv substation as the main power source Solar resource:the average possible sunshine duration is 4452.7 hours/year, sunshine duration 2916.5 hours, and shine percentage of 66%. Daytime in summer 5 am-19pm, and 8 am-17 pm in winter. Wind resource: the annual wind speed is 7.2m/s at 70m height, the annual wind power density is 504.0W/m2 as level 4, and effective wind speed hours could reach 7318h/year(3~25m/s) with steady direction. load demand: 100 households farmers (herdsman), with about 100kW power consumption, and 10kW for diary farm.

3 Implementation Example System Overview-Microgrid project in east Inner Mongolia 35kV Overhead Line,53.4kM Long Dong wu Zhu'er Substation(35kV) He'er Hongde Immigrant Village Box Type Substation PV Array 50kWp Wind Driven Generator 30kW PV Array 30kWp Lithum Battery Storage 50kWh Wind Power Generation 20kW PV Array 30kWp DGs Station Power Reserve 76 Households in East Village 24 Households in West Village Diary Farm Distribution Network Electric Optical Fiber to the Home(OPLC) MG P18 18

3 Implementation Example Hierarchical & Coordinated Control -Microgrid project in east Inner Mongolia Coordinated control and optimal operation Distribution Network Dispatching Layer Distribution Network Dispatching Center Conduct global dispatching of microgrids in the area, ensuring the safe and stable operation of distribution network Microgrid Central Control Layer Micro-power/Energy Storage/Load Local Control Layer Modbus TCP RS485 Energy Management Master Station IEC 104 Ethernet Microgrid Central Controller Operation Monitoring Subsystem Energy Management Subsystem Real-time Dispatching Strategy of Micro-power and Energy Storage Responsible for the coordinated control and optimal operation of local microgrid Energy Storage Controller Energy Storage Micro-power Controller Micro-power Controller Micropower Micropower Protection at Point of MG Connection Line Protection Load Controller Load Load Controller Load Realizing the local control and protection of DER, ESS and load 19

Site Pictures

Screenshot in Dispatching Center

Screenshot in Dispatching Center

4 Summary Microgrid Transforming the multiple connections of DERs to a single connection of microgrid Effectively integrate DERs with distribution network Realize optimized operation and control of DERs with coordination of Distribution 23 Management System in dispatching center

Thank you! yuhui3@epri.sgcc.com.cn luanwenpeng@epri.sgcc.com.cn 24