Breaking transmission barriers among provinces: A unified power system planning in China to achieve carbon neutrality

In order to actively fulfill its international treaty obligations, China has established the goal of peaking CO2 emissions by 2030 and achieving carbon neutrality by 2060. Since 2018, when ecological civilization was written into the Constitution, the realization of carbon peak and neutrality goals has had an ideological foundation and a constitutional basis. China has formulated various special laws and built a 1 + N policy system to reduce carbon emissions, which together with the environmental protection law, climate change law, energy law and other related laws and regulations constitute a unified legal system and provide legal support to achieve carbon peak and neutrality goals. At the same time, China has taken advantage of the new national system with concentrated efforts and resources to delineate the different roles of the government and market mechanisms in carbon emission reduction, and to make the operation of the legal system of carbon peak and neutrality suitable for its actual situation by giving full paly to the initiative of both central and local governments. This article analyzes the current legal system and its characteristics in China in the process of achieving carbon peak and neutrality goals in the context of the new era, and outlooks on the improvement path of the legal system from both domestic and international dimensions. The practice, experience and development direction of China in the construction of the legal guarantee for carbon peak and neutrality goals can provide reference for other countries to achieve carbon reduction.

The importance of this paper is to evaluate the reliability of the unified power system arising from the necessity of the recognaition of the network problems, the availability of the generating units and the voltage and frequency variation limits in case of network accidents and the failure rates of the power plants components as a step towards the collection of this data. The probability of forced outage of the different generating units and the spinning reserve of the united power system are calculated by three methods: the binomial distribution method, the poisson method and monte carlo method which are usually used to determine both short and long term operating reserve requirement. For computing the forced outage race of the different generating stations, the statistical data of the different units has been used. Computer programs were designed compiled and applied. 40% of the forced outage events of the steam units are due to boiler problems, the average outage hours due to boiler problems is in general higher than those of the other system problems except the turbine problems which are equal. The condenser problems causes 15.5% of the total forced outage events of the steam units which requires further study of the boiler and condenser problems in order to reduce the number of outage events and the average outage hours. The unified power system problems causes 8.7% of the total outage events of the steam units and 11% of the total forced outage events of the gas turbine units.

The EU Electricity Directive aims at extension of the competitive electricity market on the European continent. Russia and its Unified Power System (UPS) have objective prerequisites to become an equal and one of the major partners of the European electricity market. Expediency and efficiency for the UPS of Russia to participate as an equal partner of the European electricity market as well as the appropriate interaction with power systems of the CIS countries should underlie the policy for development of the electric utility industry and the UPS of Russia. Selection of the best scenarios of energy cooperation development on the European continent should be directed to creation of the common market of electricity and power as a basis of the common energy space. A number of international projects aimed at solution of this problem are implemented with the participation of Russia.

Due to uncertain load deviations in the unified power system, it becomes more challenging to uphold the system frequency at a constant desired value. The secondary controller has a significant role in damping the oscillations of frequency and interline power at a faster rate. Here a novel PI/PD dual mode controller (DMC) is suggested to regulate the frequency of unified system comprising renewable and conventional sources of power generation. The various sources of generation instigated in the dual-area system are hydro, diesel, thermal, PV, wind and battery energy storage system (BESS). The gains of the PI/PD DMC are suitably obtained by the novel application of quasi opposition based Sine Cosine Algorithm (QOBSCA) algorithm. The dynamic outcomes of the model are examined with the application of abrupt load deviation of 0.02 per unit in control area 2. During this deviated loading condition QOBSCA algorithm is utilized to achieve the appropriate gains of PID and PI/PD dual mode controller in view of a time based fitness function denoted as integral time absolute error (ITAE). Considering few response evaluative indices like overshoots, settling time and undershoots the ascendency of the projected PI/PD dual mode controller is recognized over popular PID controller during the abnormal loading condition. Additionally, the efficacy of the mentioned PI/PD dual mode controller is verified by applying arbitrary load pattern in control area 2. The robustness of the mentioned control schemes is also evidenced by confirming the stable response during system parameter deviations.

In recent decades the power system has become a complex network, to design a load frequency control (LFC) requires solving a complex equation. Optimisation techniques are essentially required to optimise the parameters of different controllers used for LFC issues in the power system. In a unified power system, the LFC is examined from all angles using different optimisation strategies to optimise the conventional PI, PID, cascaded, and fuzzy controllers as well as recently designed controllers. This manuscript specifically reviews the use of soft computing techniques in the frequency regulation of the power system with single/multiple areas that include conventional, renewable, and combinations of both, with FACTS devices and certain energy storage devices such as superconductor magnetic energy storage (SMES) and battery sources. Furthermore, deregulated power systems and microgrids are also considered for the study. To regulate LFC under various disturbances such as generation rate constraints (GRC) and dead band control, a few additional control approaches are utilised. Models of the power system are discussed and analysed. In addition, the merits and drawbacks of the studied techniques/structures that address design and implementation issues—as well as control issues that relate to the LFC problems—have been discussed.

The urgency of the problem. The most important condition for ensuring the safety of navigation and reducing accidents in the fleet is to take into account the maneuverability of ships, and especially their inertial characteristics. Electric propulsion vessels have the best maneuverability. Special attention is paid to the issues of control of electrical propulsion plants (EPP) of electric ships during maneuvers. Recently, more and more electric ships with a unified electric power system (UEPS) are being built. Both electrical propulsion plant and electricity consumers of electric ships with the UEPS are supplied with power from the general tires of the ship power plant and have a mutual influence on each other. This effect should be taken into account when optimizing the control of the electrical propulsion plant. The status of the issue. Quality indicators of electric ships’ maneuvering were determined and quality indicators of electric energy of the ship network were selected. A method of optimizing the parameters of the control laws of EPP has been developed. The transition to optimal control leads to an increase in the load on the propulsion motors and on the generating units. This may affect the quality indicators of the electric energy of the ship network. The study of this influence is the purpose of this work. The method of solving the problem. A mathematical model of EPP transient modes as part of the ship propulsion complex is used to evaluate the maneuvering characteristics of electric ships. A method of calculating transient modes of operation during maneuvering has been developed on its basis. It is proposed to form the control signals for frequency and voltage in the form of polynomials. A method of optimizing the parameters of control laws has been developed. The results of the study. Effects of load changes on optimal control laws are the following: load decrease slightly affects the optimal solution; with an abrupt increase in the load the stopping distance grows. The optimal parameters of the control laws vary slightly. The impact of the transition from the classical to the optimal control is the following: the quality indicators of the electric energy of the ship network are deteriorating, but are within acceptable limits. Conclusions. The search for optimal control laws of EPP during maneuvering for electric ships with a unified electric power system can be carried out without taking into account the switching on and off of ship consumers. The change of load in the ship network affects the value of the target function but does not affect the optimal parameters of the control laws.

Combined propulsion plants get wide spread on modern ships of foreign construction, while in the domestic shipbuilding industry there is practically no experience in the design and testing of these vessels. A distinctive feature of the combined propulsion plants is that the energy for the vessel movement is generated in them in two (or more) different types of ship engines - thermal and electric, working on a common propulsion unit - a propeller. Combined propulsion plants are complex electromechanical systems designed to ensure the movement of the vessel and the production of electricity in the various modes of operation. Combined propulsion plants conjoin the advantages of traditional propulsion systems with heat main engines and electric propulsion plants. A unified electric power system with a combined plant of a work boat is discussed in the paper. The work boat is the first vessel built in the Russian Federation with this type of propulsion system. The feature the combined propulsion plant installed on the work boat is the ability to operate the propeller electric motor in both propulsion and generator modes. The ship uses diesel generators, storage batteries and electric propulsion motor in the generator mode as the sources of electricity. The main modes of the vessel operation, the results of dock and sea trials of the unified electric power system and combined propulsion plant are briefly discussed in the paper. During the trials, the autonomous mode of operation of each electric power source on the auxiliary electric propulsion plant and ship consumers has been checked successfully. New method of synchronization of diesel-generator and autonomous inverter has been realized; it has high speed and accuracy that excludes appearance of current shot when power source connects to the main switchboard.

Fault simulation is one of the main components of dynamic electric power system simulation programs. In this work, a fault-branch based admittance matrix was used to simulate a variety of multiple symmetrical or asymmetrical faults in unified dynamic power system simulation software. Admittance matrix contraction was employed to process multiple faults and random faults. An important feature of this method is its ability to process any faults in a branch without the addition of new branches or nodes, which improves the calculation efficiency and the usability of the software.

Achieving carbon neutrality by 2060 is an ambitious goal to promote the green transition of economy and society in China. Highly relying on coal and contributing nearly half of CO2 emission, power industry is the key area for reaching carbon-neutral goal. On basis of carbon balance, a criterial equation of carbon neutral for power system is provided. By means of the equation, the different effects of three technical approaches to achieve carbon neutrality, including energy efficiency improvement, shifting energy structure and CO2 capture, utilization and storage (CCUS) technology, had been evaluated. The results indicate that building a carbon-neutral power system requires comprehensive coordination between energy efficiency, renewable energy and CCUS technology. In particular, the unique role of CCUS in achieving carbon neutral target was investigated. For any power systems with fossil energy input, CCUS and negative emission technologies is indispensable to reach carbon neutrality. However, rather high energy consumption and costs is the critical gas deterring the large scale deployment of CCUS. Considering the specific conditions of China’s power industry, before the time window between 2030 and 2040 being closed, CCUS would either be ready for large scale deployment by reducing energy consumption and costs, or be phased out along with the most coal power plants. Conclusively, carbon neutral scenario will give CCUS the last chance to decarbonize the fossil fuel, which has great significance for China.

This paper presents an approach for applying a distributed control system (DCS) for a unified power system. It is well known that the distributed control system usually serves to control large-scale systems, such as unified power systems, production lines in factories, airplanes, and airport earth services. The proposed distributed control system consists of hardware, software and a number of controllers connected through a communication protocol to develop high speed reliable data communications through the various processing elements. This goal can be evaluated by prediction of loading conditions before designing the distributed control system features. The hardware consists of digital input, digital output, analog input, and analog output devices. The software consists of process control, PC, and database systems. The proposed system is examined through a sample controller connected to the Aswan hydraulic power plant to indicate its effect on the studied system response through its fastness and robustness performance. The results indicate the robustness, and very fast response of the proposed distributed control system over the conventional one.

The proposed research article presents an optimum Fuzzy-PID controller with a derivative filter to stabilize the frequency in a unified power system which includes renewable sources of energy like solar thermal power generating units. The scrutinized system consist of two area unified power system where each area is consisting of a thermal unit with reheat turbine and a solar thermal unit. The automatic generation control is exercised in each area with the help of two distinct Fuzzy-PIDF controllers. A novel optimization method named the Grey Wolf Optimizer is applied for optimizing the coefficients of the proposed fuzzy-PIDF controller. A time dependent objective function (Integral Time Absolute Error) has been employed in this case as fitness function. Different controllers such as PID, Fuzzy-PID and Fuzzy-PIDF are used to stabilize the frequency oscillation as well as tie-line power variation in the multi-area system subject to a disturbance of 0.01 p.u. in the system. The efficacy of the recommended Fuzzy-PIDF controller is also established in view of various time domain specifications like minimum undershoots, settling time and maximum overshoots. To check the robustness and sensitiveness of the controller, the system is subjected to random loading and parameter variations.

The power system of Russian Federation is diversified regionally and consists of one Unified Power System and multiple off-grid power systems. Many parts of Russia are not connected to centralized power supply by virtue of their geographical position. There are more than five thousand autonomous energy sources in the off-grid territories, which are mainly represented by diesel power plants and gas turbines. These power plants use very expensive fossil fuel. It is proposed to use a large share of generation based on renewable energy sources (RES) for such systems. Taking into account a nonstationary character of power generation, presence of electricity storage devices, as well as stricter requirements of consumers to power quality and reliability of power supply, we can say that operating conditions of such systems and their control represent a difficult problem that needs to be studied. The tasks of substantiating the development of isolated power supply systems are considered. The analysis of the essence and level of study of task groups to substantiate the development of such systems in a hierarchical sequence is given. The problem of substantiating development is presented in the form of three successive stages: substantiating a rational configuration of the power supply system, comprehensive optimization of the structure and parameters of the power supply system taking into account various requirements and studying the operating conditions. In the paper, the specific features of microgrid operation in different seasons of a year and different time of a day are analyzed, a set of problems related to control of operation is formulated and specific features of their solution are discussed.

The results of analysis of the operating mode of power system of the Republic Moldova when accomplishing the interconnection with the power system of Romania using the Back-to-Back (BtB) power unit at the transformer station Vulcanesti have been presented in the paper. Installation of BtB leads to the loading of overhead power line (OPL) 330kV Vulcanesti-Chisinau up to 571 MW with the change of the value and the direction of power flux in OPL from Chisinau toward Kuchurgan power station, the decrease of power flux entering the north of the country (OPL 330kV HPP Dnestrovsk - Balti) and in the OPL 330kV (Kotovsk- Kuchurgan power station). Essential changes of the active power flux occur at the buses of Kuchurgan power station toward Ukraine in comparison with the actual topology of power network (base regime). The change of the direction and of values of power flux through the unified power system has as a consequence the increase by 171MW (from 2961MW to 3132MW), as well as the increase by 7,1% of the losses of power in high voltage Moldovan network comparing with the base regime. It is pointed that the accomplishment of asynchronous interconnection with Romania has the impact at regional scale causing the change of power fluxes both in the power system of the Republic of Moldova and of Ukraine with Romania including the Kuchurgan power station. Assessment of financial aspects indicates to the trend of increasing of the project’s cost of the interconnection with Romania, but in the case of investment return considering the increase of the cost for the service of transmission of power is expected the necessity to increase the tariff with nearly 154% in comparison with the value of 2015 year, considering zero value of bank and inflation rates during the 10 years of investment return, as well as the constant exchange rate of MDL to EURO during the 10 years investment return period.

Isolated power system in Russia: A chance for renewable energies?

In the field of electrical engineering, there is an increasing concern among managers and operators about the secure and cost-efficient operation of smart power systems in response to disturbances caused by physical cyber attacks and natural disasters. This paper introduces an innovative framework for the hybrid, coordinated control of Unified Power Flow Controllers (UPFCs) and Power System Stabilizers (PSSs) within a power system. The primary objective of this framework is to enhance the system’s security metrics, including stability and resilience, while also considering the operational costs associated with defending against cyber-physical attacks. The main novelty of this paper lies in the introduction of a real-time online framework that optimally coordinates a power system stabilizer, power oscillation damper, and unified power flow controller to enhance the power system’s resilience against transient disturbances caused by cyber-physical attacks. The proposed approach considers technical performance indicators of power systems, such as voltage fluctuations and losses, in addition to economic objectives, when determining the optimal dynamic coordination of UPFCs and PSSs—aspects that have been neglected in previous modern research. To address the optimization problem, a novel multi-objective search algorithm inspired by Harris hawks, known as the Multi-Objective Harris Hawks (MOHH) algorithm, was developed. This algorithm is crucial in identifying the optimal controller coefficient settings. The proposed methodology was tested using standard IEEE9-bus and IEEE39-bus test systems. Simulation results demonstrate the effectiveness and efficiency of this approach in achieving optimal system recovery, both technically and economically, in the face of cyber-physical attacks.