4 Key Smart Grid Technologies for the New Power System: Innovations in Distribution Networks

1. R&D of New Materials and Equipment & Asset Management

1.1 R&D of New Materials and New Components

Various new materials serve as the direct carriers for energy conversion, power transmission, and operation control in new-type power distribution and consumption systems, directly determining operational efficiency, safety, reliability, and system costs. For instance:

• New conductive materials can reduce energy consumption, addressing issues such as energy shortage and environmental pollution.

• Advanced electrical magnetic materials applied in smart grid sensors help improve the reliability of system operation.

• New insulating materials and insulation structures can resolve the more frequent transient pulse overvoltage problems caused by the integration of power electronic equipment.

• Next-generation microwave radio frequency devices and power electronic devices developed based on third-generation semiconductor materials (represented by gallium nitride (GaN) and silicon carbide (SiC)) can provide technical support for energy conservation and consumption reduction in the communication and electronic fields.

1.2 R&D of New Power Equipment and Electricity Consumption Facilities

In terms of specific new products, enterprises develop new power electronic equipment—especially soft normally-open switchgear. By controlling the active and reactive power flows on connected feeders, these devices achieve functions such as power balancing, voltage improvement, load transfer, and fault current limitation.

Amid the wave of the Energy Internet, integrating new technologies to realize "function + monitoring + electronization + digitalization + artificial intelligence" enables enterprises to move beyond low-end imitation to high-end manufacturing, expand from single products to comprehensive solutions, and transform from manufacturing factories to innovation-driven facilities. This allows low-voltage electrical equipment manufacturing and innovation to contribute to low-carbonization, digitalization, and sustainable development.

1.3 Full-Lifecycle Asset Management Technology for Power Equipment

New-type power distribution and consumption systems involve a wide variety of new power equipment and electricity consumption devices, making full-lifecycle management and ecological design of power distribution equipment extremely important. It is essential to ensure the safe operation of all equipment while achieving economic efficiency.

Full-lifecycle operation and maintenance covers the procurement demand phase, equipment acceptance phase, production and operation phase, and decommissioning phase. In asset management, integrated design should be implemented to ensure data sharing and optimized management. Technologies such as "Internet +" should be integrated to expand the scope of management and improve management efficiency.

2. Distributed Generation and Microgrid Technology

2.1Distributed New Energy Generation Technology

2.1.1 Efficient and Economical New Energy & Renewable Energy Development Technology

With advancements in new energy development technologies, some renewable energy sources (e.g., wind and solar energy) have reached a high level of application and now occupy a dominant position in power distribution systems. However, it remains crucial to develop new materials and integrated photovoltaic panel technologies with lower costs and higher efficiency.

Meanwhile, the development of other energy sources—such as hydrogen energy, geothermal energy, and biomass energy—needs to be further promoted. Examples include hydrogen production-storage-transportation technologies, multi-stage geothermal utilization technologies, and biofuel technologies.

In addition, coordinated development of centralized and distributed new energy can reduce transmission losses, improve new energy utilization efficiency, and enhance the grid’s ability to absorb new energy, thereby delivering better social and economic benefits.

2.2 Planning Technology for Distributed Energy

The key to addressing the planning and optimization of distributed energy ownership lies in breaking down information communication barriers and dispatching coordination barriers among different entities.

From a technical perspective, more technical constraints must be considered during the planning phase, including voltage level, short-circuit current level, and power quality (flicker, harmonics).

From a mathematical perspective, planning methods involving multi-objective and multi-uncertainty combinatorial optimization are highly complex. Therefore, multi-objective optimization planning that integrates resources and operations is critical.

Furthermore, attention should be paid to: conducting network analysis and evaluation for systems with distributed energy; researching the integration and optimal planning of power distribution systems and communication networks; and developing models and simulation tools for comprehensive reliability, risk, and economic analysis.

2.3 Active Support Technology for Distributed New Energy Generation

Distributed generation (DG) needs to not only adjust frequency and voltage within a certain range but also suppress rapid changes in frequency and voltage.

At present, some scholars have proposed an "inertia-stiffness compensator," which enables DG to provide instantaneous frequency and voltage support when the system experiences power deficits. The frequency inertia support capability of DG is quantitatively expressed using the active power compensation provided during power step changes, providing a basis for formulating subsequent grid-connection standards.

2.4 Output Prediction Technology for Distributed New Energy Generation

Distributed new energy generation features wide spatial distribution, complex surrounding micro-meteorological characteristics, and significant impacts from buildings and human activities, making output prediction challenging.

Current research on distributed new energy generation output mainly focuses on using weather forecasts and climatic conditions for power generation prediction, with excessive emphasis on the impact of natural conditions on new energy output. It lacks consideration of the spatial distribution characteristics of DG and factors related to human social activities.

2.5 Cluster Control Technology for Distributed New Energy Generation

Distributed control is an ideal cluster control method for DG in power distribution systems with high new energy penetration.

Currently, research on cluster control technology for distributed new energy generation is still in its infancy. Relevant achievements mainly focus on the control of single power generation devices, with little consideration of coordinated control strategies for multiple new energy generation devices connected to the system via grid-connected inverters.

Key issues remain unresolved: the mechanism of unbalanced power distribution among multiple inverters during power step changes; the interaction mechanism of multi-time-scale control strategies for multiple inverters; and the inadequacy of traditional droop control (based on active power-frequency and reactive power-voltage characteristic curves) when the resistance of power distribution lines is non-negligible, which prevents DG from participating in primary frequency and voltage regulation.

2.6 Distributed Energy Storage Technology

From a power perspective, the static and dynamic issues of new-type power distribution systems are essentially power imbalance problems on different time scales:

• On the relatively long time scale of peak load periods, power imbalance between the generation and load sides leads to static issues such as peak-valley differences.

• On the relatively short time scale from power step changes to the activation of primary frequency/voltage regulation, power electronic equipment lacks the rotor inertia of synchronous generators and cannot support the system against power imbalance, resulting in reduced system stability and deteriorated power quality.

Distributed energy storage technology provides a feasible solution to address the static and dynamic issues caused by power imbalance across different time scales.

2.6.1 Peak Shaving and Frequency Regulation Technology for Energy Storage

Energy-type energy storage—represented by distributed pumped storage, flow batteries, lithium-ion batteries, and cold/heat storage technologies—can eliminate load peaks, shave peaks and fill valleys, smooth fluctuations, and operate in conjunction with charging piles to mitigate charging power impacts, thereby improving the utilization rate of power distribution equipment.

Peak shaving and frequency regulation technology for energy storage imposes high requirements on energy storage systems in terms of capacity, response speed, cost, safety, and power/energy density. A single energy storage type cannot meet these requirements, so research on hybrid energy storage technologies with comprehensive advantages is necessary.

2.6.2 Stability and Power Quality Enhancement Technology

Distributed energy storage technology provides a feasible solution to improve the stability and power quality of new-type power distribution systems.

Some scholars have proposed a method that coordinates energy storage systems with grid-connected inverter control strategies to enable DG to provide dynamic stability support to the system. With the large-scale integration of power electronic equipment reducing system inertia, grid-connected inverters combined with energy storage will become an important means to enhance system dynamic stability.

In addition, power-type energy storage—represented by supercapacitors—features fast response capabilities and plays a key role in improving the power quality of power distribution systems. Currently, large-capacity, safe, and economical energy storage devices for distributed energy storage technology have not yet been maturely applied, failing to fully meet the peak shaving needs of large-scale integration of incremental loads.

2.6.3 Microgrid Technology

Considering the coordinated control of various distributed resources at the microgrid level and equating the microgrid to a voltage/current source externally can reduce the complexity of frequency and voltage stability control in power distribution systems.

Considering power mutual assistance and dispatch optimization at the microgrid cluster level can leverage the complementary characteristics of new energy and loads in different regions to address economic dispatch issues such as DG output fluctuations and peak-valley differences.

2.6.4 Frequency and Voltage Dynamic Stability Technology for New Energy Microgrids

As a relatively independent and autonomous region, new energy microgrids face dynamic stability issues similar to those of power distribution systems.

Some scholars have proposed a voltage-source virtual synchronous generator (VSG) control strategy. VSG is a common control method to improve the dynamic frequency and voltage support capabilities of DG. Its core idea is to control grid-connected inverters to simulate the external characteristics (active power-frequency and reactive power-voltage) of synchronous generators.

The virtual inertia and damping of synchronous generators simulated by traditional VSG technology are generally fixed. Under different types of power disturbances, fixed inertia parameters cannot meet the stability and rapidity requirements of microgrid frequency dynamic regulation.

Based on the above considerations, some scholars have proposed adaptive virtual inertia control technology. Additionally, other scholars have proposed generalized droop control technology by improving traditional droop control—incorporating secondary frequency control into traditional droop control to simulate inertia and damping characteristics.

2.6.5 Macro-Control Technology for Microgrid Clusters

Key issues in the operation and control of microgrid clusters include how to achieve unified regulation of multiple microgrids and how to realize power mutual assistance and optimized operation.

Some scholars have proposed a four-level control structure for microgrid clusters, including the power distribution layer, microgrid cluster layer, microgrid layer, and unit layer.

Two main strategies are used at the microgrid cluster layer: master-slave control and peer-to-peer control.

• Master-slave control requires high communication between microgrids and imposes significant pressure on the master control unit for voltage and frequency regulation.

• Peer-to-peer control overcomes these shortcomings: each microgrid unit performs autonomous peer-to-peer control based on pre-set droop curves, without the need for communication or upper-level control.

Some scholars have proposed a control strategy for hybrid microgrid clusters composed of AC and DC microgrids. This strategy standardizes the active power-frequency characteristics of AC microgrids and the active power-voltage characteristics of DC microgrids to obtain a unified control scale, enabling peer-to-peer control of hybrid microgrid clusters.

To address the challenges of real-time dispatch optimization for microgrid clusters, some scholars have proposed a modeling method for the coordinated optimization of microgrid clusters based on a partially observable Markov decision process (POMDP) under a decentralized structure. This method enables optimization modeling based on partially observed information even under weak communication conditions and uses Lagrange multipliers to decouple the objective function, reducing solution complexity. This research provides important guidance for realizing real-time dispatch optimization of microgrid clusters with complex variables and peer-to-peer control.

3. Source-Load Interaction Technology

Flexible Load Utilization and Load Management Technology

Flexible load utilization is a key link in the future development of smart energy use and energy conservation, contributing to the development of an energy-saving society.

Research on flexible load regulation technology includes:

• Classifying and modeling flexible loads based on their characteristics to fully tap into load elasticity potential.

• Actively improving flexible load mechanisms and advancing the construction of demonstration projects.

• Using intelligent technologies to conduct differentiated analysis of user behavior and improve regulation accuracy.

Effective load management can alleviate the supply-demand imbalance in new energy systems caused by the instability of new energy and uncertainties on the load side. Currently, power load management technology already has functions such as electricity fee management, power loss management, anti-stealing electricity analysis, and data sharing.

With the development of data-driven technologies, virtual power plants, and 5G communication, power load management systems will be significantly enhanced in terms of load data prediction, load coordination control technology, and management effectiveness. This will strongly support the coordinated operation of various components (e.g., distributed generation, electric vehicles, and energy storage systems) and improve the rational utilization of resources.

3.1 Power Flow Calculation Methods Considering Source-Load Uncertainties

Power flow calculation is an important foundation for power distribution system planning and dispatch operation.

At present, some scholars have proposed power flow calculation methods that consider the uncertainties of photovoltaic and wind power output. In addition, other scholars have proposed power flow calculation methods that consider load uncertainties and uncertainties in load response to peak shaving demands.

Overall, existing research has extensively considered uncertainties in various links of source-load interaction and proposed power flow calculation methods for individual uncertainties. However, there is a lack of integrated analysis of multiple uncertainties and their coupling effects, which limits the accuracy of power flow calculation in complex new-type power distribution systems.

3.2 Multi-Objective Optimal Dispatch Technology for Power Distribution Systems Under Source-Load Interaction Mode

Under the source-load interaction mode, dispatch decisions largely affect the safety and reliability of system operation.

Currently, some scholars have proposed multi-objective power flow optimization solutions using second-order cone optimization and particle swarm optimization algorithms. These solutions use Pareto optimal solution sets to conduct multi-dimensional evaluations of potential optimal solutions, providing dispatchers with more flexible decision-making options and facilitating the realization of safe, stable, and economical dispatch under the source-load interaction mode.

3.3 Economic Operation Technology in the Power Market Environment

Guiding multiple entities to participate in power market transactions through various incentive methods is an important means to promote source-load interaction. Specific technical forms include demand response (DR) and virtual power plants (VPPs).

Currently, relevant research focuses on using price incentive mechanisms to stimulate users’ enthusiasm for participation. To fully tap into and mobilize adjustable resources in the system, some scholars have conducted research on: overall situational awareness of source-grid-load; real-time quantitative evaluation of response capabilities; implementation of response strategies from group to individual; source-grid-load coordinated control technology; and multi-time-scale characteristics of loads. This research provides ideas for the development of system dynamic power balance technology based on demand response.

Research on source-load interaction mainly focuses on two aspects: power flow analysis and optimization technology, and market guidance mechanisms.

In terms of power flow analysis and optimization technology, existing technologies ignore the spatiotemporal coupling characteristics and temperature correlation characteristics caused by source-load aggregation in power distribution systems, making it difficult to improve the power flow control accuracy of new-type power distribution systems and achieve peak-valley difference smoothing on short time scales.

In terms of market guidance mechanisms, considering the inevitable time delay of load response, demand response cannot perfectly solve the peak-valley difference problem of power distribution systems. It is necessary to integrate deep flexible load control technology to enable load energy consumption curves to track new energy generation curves in real time, thereby achieving real-time source-load balance, fundamentally solving the peak-valley difference problem, and improving the utilization rate of power distribution equipment.

4. DC Power Distribution Technology

Currently, research on DC power distribution technology mainly focuses on the following aspects:

4.1 Voltage Sequence and Standardization

There is currently no unified international standard for DC power distribution voltage level sequences.

Scholars at home and abroad have proposed various DC voltage level sequence selection schemes based on factors such as power supply capacity, investment costs, DC equipment manufacturing levels, power quality requirements, power distribution economics, and load demand characteristics of various typical power distribution scenarios.

China issued the GB/T 35727—2017 Guidelines for Medium and Low Voltage DC Power Distribution Voltages in December 2017. Currently, relevant standards focus on the planning of voltage levels for medium and low voltage public DC power distribution systems, while there is a lack of detailed standards for DC voltage level sequence planning in specific scenarios such as communication systems, building power supply, ship power supply, and urban rail transit.

4.2 Fault Protection Technology for DC Power Distribution Systems

Fault protection technology is a key means to ensure the safe operation of DC power distribution networks.

The emergence of new power distribution equipment (represented by two-level voltage source converters and modular multilevel converters) and ring network topologies has profoundly changed the fault characteristics of power distribution networks.

Some scholars have proposed protection strategies based on current direction comparison, extreme value comparison, direction prediction, and "single-branch real-time memory, multi-branch short-time location," which have improved the speed of fault type identification and the reliability of fault isolation.

4.3 Coordinated Control and Dispatch Optimization Technology for DC Power Distribution Systems

Currently, the voltage control strategies for DC power distribution networks mainly include three methods: master-slave control, droop control, and voltage margin control.

Based on the experience of DC power distribution network demonstration projects, master-slave control is the most widely used voltage control method for DC power distribution networks at this stage.

Some scholars have proposed improved voltage control strategies, such as a DC voltage deviation slope control strategy that combines droop control and deviation control. This strategy overcomes the slow response speed of deviation control and the steady-state error of droop control.

With the large-scale integration of distributed generation, energy storage, and flexible loads, microgrids will become an important way to achieve friendly integration and efficient absorption of new energy in power distribution systems. The coordinated control technology of AC/DC microgrid clusters combined with DC power distribution technology is a research direction worthy of attention in the future.

5. Digital Power Distribution Network Technology

5.1 Intelligent Technology for Electrical Equipment

The foundation of digital management technology lies in electrical equipment having data collection, computing, and communication capabilities.

• Data Collection: Compressed sensing technology can reconstruct original signals with high probability using low-rank data, which is an effective method to resolve the contradiction between sensor cost and performance in intelligent power equipment.

• Computing: How to realize algorithm lightweight and apply it to edge computing is a question worthy of attention.

• Communication: Wireless communication, optical fiber communication, and carrier communication are the main methods for power equipment to achieve remote communication at this stage. The information security of intelligent terminals is also a key issue that needs to be focused on in the research of intelligent power equipment.

5.2 Transparency Technology for Power Distribution (Micro)Grids

The various types of sensors in new-type power distribution systems generate massive amounts of electrical and non-electrical data. Through the construction of multi-state monitoring databases for equipment, digital technology enables the overall observability and controllability of new-type power distribution systems, gradually moving toward transparency.

Currently, in the multi-source data collection link of digital management technology, power distribution equipment has not yet achieved intelligence, lacking means for collecting various electrical and non-electrical data, and there is no unified standard for data upload interfaces.

In the data processing and analysis link, there is a lack of mining technology for the correlation of multi-modal and multi-type data, making it impossible to fully utilize the spatiotemporal correlation information contained in the data for power distribution operation optimization.