New power system and its digital transformation under the double carbon target

1. Background of new power system

Now many people will mention "zero carbon", but the view of "zero carbon" is wrong. All life on earth is carbon-based, including various animals, plants and organisms, and zero carbon means no life!

Carbon dioxide is an important raw material for plant photosynthesis. Studies have shown that crop yields will increase as the concentration of carbon dioxide increases. Usually, the concentration of carbon dioxide in the atmosphere is about 100-2000ppm. If it falls below 50ppm, photosynthesis will stop. Therefore, the vegetation near the chimney of thermal power plants usually grows well.

To sum up, "double carbon" is not "zero carbon". "Double carbon" means low carbon in industry and high carbon in agriculture!

As shown in the figure above, it shows the development of my country's installed capacity of power generation under the dual carbon targets. Among them, the amount of photovoltaic and wind power is basically the same. However, when the sun goes down, 4 billion photovoltaics cannot generate electricity. When the summer heat is high, 4 billion wind power cannot generate electricity.

At present, my country's total installed capacity is 2.4 billion, of which coal power accounts for 1.1 billion. However, in the case of coal power accounting for 50% in my country, the situation of coal shortage and power limitation is still very serious. Therefore, the new power system still faces five major structural security issues, namely: power supply structure, power grid structure, power consumption structure, network information, and dispatch control.

Among them, the problems of power supply structure, power grid structure, and power consumption structure are difficult to adjust. The power structure has the difficulty of having many random intermittent power sources and few fast-adjusting power sources; the power grid structure has the difficulty that the cross-regional power grid has not yet been networked, and the mutual aid ability of the entire network is poor; the power structure has poor demand-side response and high energy consumption. Difficulties.

Since electricity is transmitted at the speed of light and is not easy to store, "send, transmit, distribute, and use" are all completed in an instant, so the balance of the system must be controlled in real time. Compared with European and American countries, due to the scarcity of gas resources and the small proportion of gas turbines in my country, real-time control system balance has become more and more difficult in recent years.

In order to solve the balance problem of power dispatching, my country mainly relies on thermal power regulation. Recently, due to reasons such as rising coal prices, power supply in some areas has been tense, so it is very difficult to maintain a balance.

Large-scale new energy (photovoltaic and direct-drive wind turbines with zero inertia, and double-fed wind turbines with partial inertia) are connected to the grid, and a large amount of DC is fed into the receiving end (0 inertia) power grid, resulting in a continuous decrease in the overall effective inertia of the system and continued deterioration of the anti-disturbance capability .

The above figure is an example. In the case of Jinsu DC blockade and large power shortage on September 19, 2015, the frequency recovery process of the East China Power Grid is divided into four stages. About 0 to 3 seconds after the failure, inertial buffer adjustment, if the system inertia is small, the grid frequency will drop rapidly; about 3 to 30 seconds after the failure, a frequency modulation action will slow down the frequency drop, and gradually rise after reaching the lowest point; 30 seconds after the failure, The second frequency regulation starts, and the grid frequency continues to recover; 100 seconds after the failure, the pumped storage unit and other fast power sources start to restore and maintain the grid frequency.

According to network statistics, in the past 10 years, there have been 32 fires or explosions in energy storage power stations around the world. Most of the fires and explosions in energy storage power stations occurred during charging or after charging, and most of the accidents used ternary lithium-ion batteries.

On April 16, 2021, an accident occurred in the energy storage power station (lithium iron phosphate battery) of Beijing Guoxuan Fuweisi Solar Storage and Charging Technology Co., Ltd. The accident caused 2 firefighters to die, 1 firefighter was injured, and 1 employee in the power station died. couplet.

Compared with electrochemical energy storage power stations, the overall efficiency of the grid and urban heating network coordination method exceeds 80%, which is safer and more economical! Taking Beijing as an example, Beijing Dongjiao Thermal Power Plant coordinates and optimizes power generation and heat supply, with a total efficiency of over 80%!

Since my country's power grid uses free air insulation, the power grid's ability to resist major disasters and damage is insufficient. In addition to natural disasters such as lightning, blizzards, and wildfires, it is also unable to resist the attacks of graphite bombs and electromagnetic pulse bombs.

If underground XLPE cables or underground gas-insulated pipelines (GIL) are used, the cost is 10 to 20 times that of today.

my country's power generation resources and power loads are distributed in reverse, and the west-to-east power transmission across the Heihe-Tengchong line is the main energy flow. The UHV operation scale has reached "11 AC and 11 DC", UHV AC-DC hybrid connection, and large-scale cross-regional power transmission have become typical features of the State Grid.

"Strong straight and weak AC" in the power grid means that the AC grid is too weak and the DC grid is too strong. At present, the world-recognized technology is "DC transmission, AC networking", thus forming a flower basket structure.
However, through practice, it has been found that the biggest problem of the DC power grid is its reliability. The high-voltage DC transmission valve group is composed of hundreds of thyristors in series, which has poor reliability and large losses. Due to the serious ground bias, the voltage stability deteriorates. In order to solve this problem, a lot of cooling needs to be used, and its energy cost is higher than that of AC.

The picture above is a graph of national electricity consumption, which has obvious peak and trough characteristics.

In terms of electric vehicle energy storage, G2V and V2G have not yet formed a scale, and there are many basic problems.

In terms of micro-grid, its purpose is to achieve self-use, surplus electricity connected to the grid, independent control, and local regulation. However, the relevant technical specifications of the micro-grid need to be improved, and the bottleneck of voltage instability is prone to appear at present.

In terms of household photovoltaics and household appliances, the grid status information broadcast by the center is used to assist in judgment. The user's home business application can access the Internet through WiFi.

In terms of large-scale energy storage and large-scale power supply, the "Electricity Law" stipulates that dispatchers must be responsible for control. In terms of micro-energy storage, residents can completely autonomously control the switching on and off of energy storage equipment according to the voltage and frequency of the grid-connected point, combined with the grid accident status information broadcast by the grid dispatcher.

As shown in the figure above, there are three lines of defense for the safety and stability of the power system, which are relay protection, stability control, and de-loading control.

my country's power grid automation technology has experienced four development stages in the past 40 years: early exploration, introduction and digestion, independent development, and gradual transcendence. The digital technology transformation of the power system was completed 20 years ago, and now it is advancing towards intelligent technology, creating a new era of smart grid.

2. Smart Grid and Security Protection

The smart grid dispatching control system D5000 has been put into operation in all state grid provincial three-level dispatching and most prefectural and municipal control centers of the State Grid, forming a special cloud for power grid dispatching (about 100,000 computing nodes) and a dedicated Internet of Things (about 200 million real-time points) to realize the coordinated operation of multi-level power grid dispatching. The typical configuration of the dispatch control center above the prefecture (city) level is 300 computers (100 rack servers, 100 blade servers, 100 graphics workstations).

In the past 10 years, with the gradual construction and improvement of the smart grid dispatching control system, there are now more than 100,000 sets of computers and more than 100,000 sets of network equipment, all over the country.

In addition, my country has realized online early warning of multiple successive faults in the power grid. From the original grid operation calculation twice a year (summer and winter), it has been improved to cycle calculation every 15 minutes and real-time calculation triggered by second-level large disturbance events. For the first time in the world, it has realized real-time tracking and analysis of minute-level power grid multiple successive faults, effectively improving It improves the ability of dispatching to deal with multiple successive faults of the power grid.

The control system has its own laws, and the power system also has its own laws. As shown in the figure above, the response time of the control function is directly proportional to the operating distance. Therefore, the control system must not be concentrated in one area, otherwise it will cause very serious accidents.

At present, my country's smart grid system has formed a series of standards, of which the five most important standards are: general graphical interface, general service interface, general model description, general communication protocol, and general security protection. my country's smart grid standards have contributed two normative guidelines to the International Electrotechnical Commission ICE, which is enough to show that the system is already a world leader.

At present, my country's smart grid has become the largest in the world. Digitization (informatization), automation, and intelligence must meet the practical requirements of the power system.

Since semiconductor devices are high-energy-consuming devices, it is necessary to beware of excessive intelligence, resulting in unnecessary high energy consumption (such as Bitcoin mining, etc.).

In recent years, the country has carried out several times of intelligent power primary equipment. Taking the video surveillance isolation switch as an example, it caused a lot of waste of resources.

Therefore, excessive intelligence has also brought many problems, such as the decline in reliability of primary equipment after intelligentization; the life of primary and secondary equipment does not match; most intelligent equipment is not practical; the number of real-time measurement points in substations has increased by more than 10 times.

How to improve the quality of primary equipment itself? How to improve the practical level of smart devices? How to prevent over-digitization and over-intelligence? It is a problem that everyone needs to think about and start to solve.

In terms of smart meters and electricity consumption information collection, there are security risks in the remote control of the public network. In the future, only the non-real-time remote meter reading function may be retained. Internet companies need to highly strengthen the protection of users' sensitive data and private information.

At present, the threat situation of network security is becoming more and more serious. Only during the Olympic Games in August 2008 (2 weeks), the Olympic power grid was attacked by external networks 8939 times.

In May 2017, Google discovered that Intel's CPU had a built-in Minix operating system, and soon Google's tensor processor TPU was also found to have vulnerabilities, and later found hidden dangers such as meltdown, ghost spectre, POP SS, and zombie load. All support Processors with out-of-order execution and branch prediction (CPU, GPU, TPU, etc.) have problems. It can be seen that network security threats develop from software to hardware.

As shown in the figure above, in recent years, the frequency of my country's power grids suffering malicious attacks from external networks has increased. At present, my country's power grid is attacked every 8 seconds on average, and more than 10,000 attacks are encountered every day. During major national events, the frequency of malicious external network attacks on the power grid is several times higher than usual!

To sum up, industrial control systems need endogenous security, that is, the three-in-one of functional security, cryptography, and network security. Suitable for industrial systems SCADA, DCS, CCS, PLC, etc.

Although the business characteristics of various industrial fields are very different, and the protection measures are not the same, the network security protection system is the same! In the industrial field, GB/Z41288-2022 is the guideline for network security protection of important industrial control systems, and is the hard system of network security in the industrial field.

The important industrial control system network security protection system (TEMt) mainly conducts industrial network security protection in three dimensions: comprehensive security management, emergency backup measures, and security protection measures.

In terms of endogenous security, it is necessary to ensure that the monitoring system has no malicious software, the operating system has no malicious backdoors, the motherboard of the whole machine has no malicious chips, the main chips have no malicious instructions, and trusted computing security immunity.

According to the latest national standards, the private cloud available for important industrial engineering industries must be effectively and securely isolated from the private cloud managed by the enterprise, and social public clouds must not be used to avoid information leakage and protect the network security of industrial systems.

In terms of key industrial control, in order to avoid the interconnection of all things and the smog, industrial control can use a dedicated Internet of Things to realize on-demand interconnection and ensure the safety of the country's industrial property.

The "zero trust" architecture is to add a layer of identity-based logical security boundaries on the basis of boundary security protection, and migrate access control from the coarse-grained network boundary level to the fine-grained level of all subjects, objects, and services. Identity verification and authority control of people, equipment, access requests, etc., to achieve both internal and external defense, self-demolition of the border is equal to self-destruction of the Great Wall!

It can be seen that the industrial cloud requires hardware to be cluster-oriented and software to be service-oriented. Among them, the hardware includes multi-core many-core chips, symmetric multi-processing SMP, and server cluster NUMA. Software services including virtualization, network grid, and cloud computing

3. Digital transformation of the power industry

Industrial control systems should be business-centric, not data-centric. The whole system is divided into foreground, middle platform and backstage. Among them, the foreground is the access layer of the business, the middle platform is the application layer of the business, and the background is the database layer of the business.

As shown in the figure above, the model is oriented to the business through the data. After the industrial big data is distributed and processed, it becomes the industrial small data, which realizes millisecond-level calculation. In addition, data without a business model is garbage data. False numbers are counted as true, and counts are counted eastward and westward. They leave the business and are purely a waste of electricity.

The current artificial intelligence has well-developed limbs, handsome facial features, and simple thinking, and is still in the growth stage. If artificial intelligence is used in power system and production control system, it must be combined with power system model. AI real-time closed-loop control without a business model has major security risks!

At present, a variety of optical fiber communications are suitable for industrial control services. Among them, visible light communication inherits the advantages of optical communication, anti-electromagnetic interference, waterproof and oil-proof, strong confidentiality, no risk of information leakage, and compared with laser communication, although the rate is lower (100K~100Mbps), the medium is easy to process ( Just cut), resistant to harsh environments (bending, vibration, wear), and more adaptable to industrial site environments. It is also easy to combine with the wireless optical communication LiFi at the end, and is suitable for intelligent electronic traffic signal services.

Because wireless communication is oriented to moving targets, power plants, substations, transmission lines, and power buildings do not move, so fixed services do not require wireless private networks. Metal reflections, electromagnetic interference, and dusty environments in factories, stations, and workshops have great interference with wireless communications. Therefore, in order to adapt to fixed services, the F5G mode of optical fiber + wireless should be adopted.

As shown in the figure above, traditional application systems and traditional industrial control systems need to be gradually upgraded to new distributed industrial control systems, which are connected by industrial control networks to further ensure the safety of industrial production and improve the efficiency of industrial production.

In order to solve the three major structural problems, market mechanisms or electricity price policies are urgently needed. At present, the most effective method is bilateral peak and valley electricity prices: promoting the balance between the power generation side and the power consumption side is the most effective! The overall electricity price and the average electricity price level remain unchanged, with a 30% increase during peak hours and a 30% decrease during trough periods, which can be formulated by the provincial development and reform commissions according to the specific conditions of each region, and gradually transition to the electricity market.

As shown in the figure above, it takes 50-100 years to solve the power structure problem, and 10-20 years to solve the power grid structure problem, but the solution to the power structure problem can be effective on the same day!

The core goal of the new power system is to make the power system safer, more cost-effective, greener, more practical and friendly.

Enterprises need to pay attention to the fact that in the new power system, the structure of the main grid of the power grid, the hierarchical control method, the security protection system, and the power communication network have not changed.

The government and enterprises must guard against excessive double-carbon zero-carbonization, excessive batteryization of energy storage, excessive direct current of the power grid, excessive wireless communication, excessive intelligentization of equipment, and excessive digitalization of business.

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