Hybrid power generation and transmission system, and managing method for same

Abstract

The present invention provides a hybrid power generation and transmission system and a management method for same. The hybrid power generation and transmission system, according to an embodiment of the present invention, comprises: an ESS installed in a base power station and storing surplus electricity among electricity generated in the base power station; and a control device for controlling the surplus electricity to be transmitted from the ESS to a distribution system by using a high voltage direct current (HVDC) transmission technology. At this time, the surplus electricity is transmitted from the ESS to the distribution system through a transmission line used for alternating current (AC) transmission.

Description

Hybrid power generation and transmission system and its management method

[0001] The present invention relates to a hybrid power generation and transmission system and a management method thereof, and more particularly, to a hybrid power generation and transmission system using high-voltage direct current (HVDC) transmission technology and a management method thereof.

[0002] South Korea's power grid is managed to maintain world-class stability. Compared to advanced countries like the US, Germany, and Japan, power loss during transmission and distribution is lower, and the entire power grid is organically interconnected, enabling real-time interconnection.

[0003] However, as population and industry continue to be concentrated in the metropolitan area, the regional power imbalance has worsened, posing significant challenges to South Korea's current power grid.

[0004] The following description is based on the South Korean power grid, but other countries may face similar issues. According to Korea Electric Power Corporation (KEPCO), South Korea's power supplier, regions such as Chungcheong, Honam, Yeongnam, and Gangwon are experiencing excess electricity production. To meet the demand in the Seoul metropolitan area, excess electricity produced outside the metropolitan area must be supplied to the capital, but the current transmission lines are inadequate. With the construction and expansion of large-scale power-consuming data centers (IDCs), semiconductor production lines, and biotech plants in the metropolitan area, it is becoming increasingly difficult to supply the necessary amount of electricity in a timely manner.

[0005] A particularly pressing issue is the lack of transmission lines to transport electricity generated in the East Coast region to other regions, including the metropolitan area. Large-scale thermal power plants along the East Coast are generating massive amounts of electricity since their operations began in 2022. However, due to a lack of transmission lines to transport this electricity to other regions, these plants are operating at around 40% of their capacity or even shutting down altogether. Furthermore, Unit 2 of the Shin Hanul Nuclear Power Plant (generation capacity: 1,400 MW), constructed in Uljin, North Gyeongsang Province, began commissioning in September 2023 and is scheduled to begin commercial operation in the first half of next year. However, there is a lack of transmission lines to transport the electricity generated.

[0006] According to the original plan, transmission lines should have been expanded before the power plant could be commissioned, but this schedule has been repeatedly delayed due to opposition from residents and delays in obtaining local government approvals. Ideally, the transmission lines should be buried underground, either through a project to bury them underground or by providing adequate compensation to nearby residents and appropriately addressing concerns about electromagnetic waves. However, the process of installing new transmission lines and towers, including new transmission systems, is no easy feat. Furthermore, Korea Electric Power Corporation (KEPCO), the company responsible for this project, is struggling with massive deficits, making it difficult to secure funding.

[0007] Due to issues such as a shortage of transmission lines, new power plants are unable to generate power at their rated capacity and are instead operating at reduced power levels. Furthermore, the completion of plants and data centers under construction in the metropolitan area is being delayed, and issues such as compensation for reduced power levels continue to arise between Korea Electric Power Corporation (KEPCO) and new power plants.

[0008] Electricity produced at a power plant but not sold or remaining at the power plant for various reasons is generally referred to as surplus electricity. Furthermore, from a macroscopic perspective, electricity lost during transmission along transmission lines, rather than reaching consumers, can also be considered surplus electricity.

[0009] Research is underway to utilize such surplus electricity by utilizing Energy Storage Systems (ESS). In this regard, Korean Patent Publication No. 10-2020-0055959 (Applicant: Korea Electric Power Corporation) discloses a thermal power plant operation control system utilizing ESS.

[0010] Meanwhile, high-voltage direct current (HVDC) transmission technology is emerging as a solution to these problems. HVDC transmission involves converting alternating current (AC) power generated at power plants into direct current (DC), transmitting it, and then reconverting it back to AC at the receiving area for power supply. Because direct current does not generate magnetic fields, it generates minimal electromagnetic waves, reduces energy loss during long-distance transmission, and enables seamless transmission between countries with different rated frequencies.

[0011] HVDC cables have a large cross-sectional area and high allowable temperature, enabling them to carry large currents through their conductors. This makes them significantly thicker and heavier than conventional transmission lines. Consequently, HVDC cables must be installed in a different manner than conventional transmission lines.

[0012] The present invention has been conceived in response to the aforementioned background technology, and the problem that the present invention seeks to solve is to provide a hybrid power generation and transmission system and a management method thereof that can transmit surplus electricity generated at a base load power plant to a power grid through existing transmission lines used for alternating current (AC) transmission without installing new transmission lines or HVDC cables.

[0013] In addition, another problem that the present invention seeks to solve is to provide a hybrid power generation and transmission system and a management method thereof that can transmit surplus electricity to the power grid with as little loss as possible during times when consumers have high electricity demand.

[0014] However, the solutions to the problems of the present invention are not limited to those mentioned above, and other solutions not mentioned will be clearly understood by those skilled in the art from the description below.

[0015] As a technical means for achieving the above-described technical task, a hybrid power generation and transmission system according to an embodiment of the present invention includes an ESS installed in a base load power plant to store surplus electricity among the electricity produced in the base load power plant; and a control device that controls the transmission of the surplus electricity from the ESS to a distribution system using high-voltage direct current (HVDC) transmission technology.

[0016] At this time, the surplus electricity is characterized in that it is transmitted from the ESS to the distribution system through a transmission line used for alternating current (AC) transmission.

[0017] In addition, in an embodiment of the present invention, the control device may be characterized in that it evaluates the rate of return according to electricity sales in the case of transmitting the electricity produced at the base power plant through the transmission line as alternating current (AC) and in the case of transmitting the surplus electricity through the transmission line as high-voltage direct current (HVDC), and determines the electricity to be transmitted to the distribution system based on the evaluation result.

[0018] In addition, in an embodiment of the present invention, the control device may be characterized by checking in real time whether the surplus electricity stored in the ESS is high voltage direct current (HVDC) that satisfies a predetermined standard.

[0019] Here, the above-mentioned standard may be characterized as a voltage of 1.5 kV or higher, which is an international standard, or a voltage of 7 kV or higher, which is a Korean standard.

[0020] Meanwhile, as a technical means for achieving the above-described technical task, a management method of a hybrid power generation and transmission system according to an embodiment of the present invention includes a step of storing surplus electricity among the electricity produced by an ESS installed in a base load power plant; and a step of controlling a control device connected to the ESS to transmit the surplus electricity from the ESS to a distribution system using high-voltage direct current (HVDC) transmission technology.

[0021] At this time, the surplus electricity is characterized in that it is transmitted from the ESS to the distribution system through a transmission line used for alternating current (AC) transmission.

[0022] According to the embodiment of the present invention described above, the following effects can be obtained by transmitting alternating current (AC) or high-voltage direct current (HVDC) through existing transmission lines included in transmission facilities of a conventional power system.

[0023] According to an embodiment of the present invention, electricity is transmitted to multiple regions using alternating current (AC) or high voltage (HVDC) transmission lines by utilizing existing transmission lines without installing new transmission lines or HVDC cables, so that problems caused by a shortage of transmission lines can be solved in a short period of time.

[0024] In addition, by using high-voltage direct current (HVDC) transmission technology according to an embodiment of the present invention, power loss occurring during alternating current transmission can be minimized, and large-capacity power can be transmitted without a step-up and step-down process.

[0025] In addition, by using high-voltage direct current (HVDC) transmission technology according to an embodiment of the present invention, no magnetic field is generated, so complaints from surrounding residents due to electromagnetic waves can be resolved.

[0026] In addition, according to an embodiment of the present invention, surplus electricity that would otherwise be wasted can be stored through ESS and then the surplus electricity (direct current) can be transmitted through existing transmission lines using high-voltage direct current (HVDC) transmission technology, thereby minimizing the construction of new power plants and transmission lines and contributing to low-carbon policies to a certain extent.

[0027] In addition, since the electricity to be transmitted to the distribution system is determined by considering the profit rate from electricity sales according to an embodiment of the present invention, the profit from electricity sales can be maximized.

[0028] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0029] Figure 1 is a schematic diagram of a conventional power system.

[0030] FIG. 2 is a schematic diagram illustrating a hybrid power generation and transmission system according to an embodiment of the present invention.

[0031] Figure 3 is a drawing for explaining the detailed configuration of the ESS shown in Figure 2.

[0032] Figure 4 is a flowchart showing a management method of a hybrid power generation and transmission system according to an embodiment of the present invention.

[0033] The advantages and features of the present invention, as well as the methods for achieving them, will become clearer with reference to the embodiments described in detail below, along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein and may be implemented in various different forms. It will be apparent to those skilled in the art that the principles and novel features disclosed herein can be applied to other embodiments without departing from the scope of the present invention.

[0034] Additionally, unless otherwise specified, the same reference numerals designate the same components throughout the specification. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention. The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings are illustrative and are not limited to the details depicted in the drawings.

[0035] Furthermore, it should be understood that the terms "comprises" and / or "comprising" in this specification imply the presence of a given feature and / or component, but do not preclude the presence or addition of one or more other features, components, and / or groups thereof. Furthermore, unless otherwise specified or clear from context to indicate a singular form, the singular should generally be construed as meaning "one or more." Furthermore, although terms such as first, second, etc. may be used to describe various components, the components should not be limited by these terms, and the terms are used only to distinguish one component from another.

[0036] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0037] Figure 1 is a schematic diagram of a conventional power system.

[0038] The conventional power grid consists of power generation facilities, transmission facilities, substation facilities, distribution facilities, and customer facilities. Electricity produced at base power plants is supplied to customers through transmission lines and substations and then through distribution lines.

[0039] For reference, this drawing is a conceptual diagram of the power system included in the press release announcing the power system innovation plan by the Ministry of Trade, Industry and Energy on December 29, 2021.

[0040] FIG. 2 is a schematic diagram illustrating a hybrid power generation and transmission system according to an embodiment of the present invention.

[0041] The hybrid power generation and transmission system largely includes power generation-related components, a hybrid transmission system, substation-related components installed at local substations, a distribution system, and consumers.

[0042] The hybrid transmission system transmits power from an ESS (100) installed in a base load power plant (10) to substations in each region, and includes transmission towers and transmission lines (20) included in the transmission facilities of a conventional power system as illustrated in Fig. 1. However, unlike the transmission facilities of a conventional power system, the hybrid transmission system may not require a substation stage for ultra-high voltage step-up and step-down.

[0043] The transmission line (20) can be designed to transmit alternating current or direct current power.

[0044] Therefore, in the embodiment of the present invention, the transmission line (20) can be used for alternating current (AC) transmission or high voltage direct current (HVDC) transmission.

[0045] Transmission lines (20) in South Korea are divided into three categories: 765kV, 345kV, and 154kV. It is natural that transmission lines (20) in other countries may be classified differently from those in South Korea, depending on national policies and local circumstances.

[0046] In an embodiment of the present invention, a 765kV, 345kV, or 154kV transmission line (20) used for alternating current (AC) transmission can be connected to an ESS (100) and utilized without any special modification.

[0047] A primary step-down substation performs the task of stepping down, for example, 765 kV to 345 kV or 345 kV to 154 kV.

[0048] Components related to substations are installed in each region and regulate voltage during the transmission and distribution process. They include substations, transformers, switching equipment, protective relays, lightning arresters, grounding devices, and distribution panels.

[0049] At this time, the substation is a secondary step-down substation that performs the task of stepping down 154 kV to 22 kV, for example.

[0050] The distribution system transmits the compressed electricity to the user (40) through the substation-related components of the local substation, and includes distribution lines (30), distribution substations, and pole-mounted transformers.

[0051] A distribution substation performs the task of stepping down, for example, 22 kV to 6.6 kV, and a pole transformer performs the task of transforming, for example, 6.6 kV to 220 V or 110 V.

[0052] Consumers (40) refer to consumers who actually use electricity, such as factories, buildings, and homes.

[0053] Power generation-related components include a base power plant (10) and an ESS (Energy Storage System; 100).

[0054] A base power plant (10) produces electricity and is connected to a transmission system to transmit the produced electricity to the transmission system.

[0055] In the embodiment of the present invention, a baseload power plant (10) may refer to a coal-fired power plant or a nuclear power plant. A baseload power plant refers to a power plant that operates continuously 24 hours a day throughout the year, excluding periods due to annual scheduled preventive maintenance, thereby forming a power base.

[0056] Power generation using renewable energy is clearly distinguished from baseload power generation in that the amount and timing of generation are irregular, making it far from stable. Renewable energy refers to both renewable energy sources such as solar, solar thermal, bio, wind, and hydropower, as well as new energy sources such as fuel cells and hydrogen energy. In other words, in the embodiment of the present invention, the baseload power plant (10) does not refer to a power plant that generates power using renewable energy.

[0057] ESS (100) can charge a portion of the electricity produced by the base power plant (10) and transmit (discharge) the charged electricity to the power grid.

[0058] For example, considering the power consumption of the user, during times of low power consumption, surplus electricity produced from the base power plant (10) is transferred to and stored in the ESS (100), and during times of high power consumption or peak time, the stored surplus electricity can be transmitted (discharged) to the power grid.

[0059] In the ESS (100) according to an embodiment of the present invention, high voltage direct current (HVDC) transmission technology is utilized, and a characteristic thereof is that a transmission line (20) of a conventional transmission system is used instead of an HVDC cable during transmission.

[0060] In addition, the ESS (100) according to an embodiment of the present invention is installed within a base load power plant (10) and can receive and store electricity produced within the base load power plant (10) while minimizing loss. There is a significant difference in the degree of power loss and economic feasibility between the ESS (100) being installed within the base load power plant (10) and the ESS (100) being installed outside the base load power plant (10).

[0061] In an embodiment of the present invention, the ESS (100) can be installed in, for example, one or more coal-fired power plants and one or more nuclear power plants.

[0062] In this case, when ESS (100) is installed in multiple coal-fired power plants and nuclear power plants, the detailed configuration of the ESS described below can be installed individually in each power plant, and in some cases, some of the detailed configurations of the ESS can be installed integrated.

[0063] Figure 3 is a drawing for explaining the detailed configuration of the ESS shown in Figure 2.

[0064] ESS (100) includes an ESS battery (110), a battery management system (BMS; 120), a power conversion system (PCS; 130), a power conversion management system (PMS; 140), and an ESS management system (EMS; 150).

[0065] An ESS (100) according to an embodiment of the present invention is connected to a transmission line (20) of a transmission system (A), and surplus electricity stored in the ESS (100) can be transmitted through an existing transmission line (20) included in a conventional power system according to a high voltage direct current (HVDC) transmission method.

[0066] The ESS battery (110) comprises a plurality of battery cells connected in series or parallel. For example, the ESS battery (110) may be configured with a plurality of racks, each rack comprising a plurality of modules connected in series, and each module comprising a plurality of battery cells connected in series. The battery cells may be, for example, lithium polymer batteries.

[0067] An ESS battery (110) according to an embodiment of the present invention can store surplus electricity among the electricity produced in a base load power plant (10) and can be installed in the base load power plant (10).

[0068] The battery management system (120) performs operations to manage and monitor the ESS battery (110).

[0069] The power conversion system (130) performs operations such as conversion between alternating current (AC) and direct current (DC) and stepping up / stepping down.

[0070] The power conversion system (130) can be designed to optionally include [1] a rectifier, power supply unit (PSU), switch mode power supply, etc. for converting alternating current to direct current, [2] an inverter, motor generator, switch mode power supply, etc. for converting direct current to alternating current, [3] a linear regulator, voltage regulator, motor generator, switch mode power supply, etc. for converting the voltage level of direct current, [4] a transformer, cycloconverter, variable frequency transformer, switch mode power supply, etc. for converting the frequency, phase, or voltage level of alternating current.

[0071] The power conversion management system (140) performs operations to control and manage the power conversion system (130).

[0072] The ESS management system (150) controls the entire ESS (100) and performs operations to manage various functions such as automatic frequency control, economic load distribution, and remote monitoring and control.

[0073] A control device according to an embodiment of the present invention may be implemented as at least one of a battery management system (120), a power conversion management system (140), and an ESS management system (150), or may be implemented in a form in which each component is integrated.

[0074] In addition, the control device according to an embodiment of the present invention can control to transmit surplus electricity from the ESS (100) to the distribution system using high voltage direct current (HVDC) transmission technology. At this time, the surplus electricity can be transmitted from the ESS (100) to a substation-related component or the distribution system through a transmission line (20) of the transmission system used for alternating current (AC) transmission.

[0075] Electricity and surplus electricity produced in base load power plants (10) are generally alternating current, and electricity inverted from alternating current to direct current by a power conversion system (130) can be stored in an ESS battery (110). The high voltage direct current (HVDC) charged in the ESS battery (110) is transmitted to the distribution system through the transmission line (20) of the transmission system used for alternating current (AC) transmission without the need for conversion to alternating current, thereby simplifying the transmission process and reducing power loss.

[0076] At this time, the transmission line (20) may be a three-phase, four-wire system, consisting of three wires (R, S, T) with a phase difference of 120 degrees and a neutral line (N).

[0077] When transmitting alternating current (AC), all three wires of the transmission line (20) must be used, but when transmitting high-voltage direct current (HVDC), the three wires of the transmission line (20) can be selectively used. That is, high-voltage direct current (HVDC) can be transmitted using some or all wires of the transmission line (20), and when transmitting high-voltage direct current (HVDC) using all of them, the amount of power transmitted can be significantly higher than when transmitting alternating current (AC).

[0078] As of 2020, the power capacity available for alternating current (AC) transmission is 240 MW at 154 kV, 900 MW at 345 kV, and 4,200 MW at 765 kV. The power capacity available for high-voltage direct current (HVDC) transmission can be two to three times that of alternating current (AC).

[0079] In particular, in the embodiment of the present invention, surplus electricity that could be discarded is stored in an ESS (100) and then the surplus electricity can be transmitted as high voltage direct current (HVDC) using a transmission line (20) of a conventional transmission system used in alternating current (AC) transmission, thereby minimizing the construction of new power plants and contributing to a low-carbon policy to a certain extent.

[0080] The table inserted below analyzes the expected effects resulting from the use of a hybrid power generation and transmission system according to an embodiment of the present invention, based on collectable objective data.

[0081] This analysis assumes that 150 MW ESSs are installed within each of South Korea's 25 operating nuclear power plants as of 2022, storing excess electricity and transmitting it via existing transmission lines within the existing power grid using high-voltage direct current (HVDC) transmission. If the capacity of each ESS were increased or ESSs were installed and operated within coal-fired power plants, the results are expected to be even better than those in the analysis below.

[0082] Specifically, using a hybrid power generation and transmission system according to an embodiment of the present invention can save 18% of coal-fired (thermal) power generation and secure approximately 20% more power compared to actual usage at consumers. Furthermore, the reduction in coal-fired power generation can reduce coal import costs by approximately KRW 3.6 trillion annually, and the sale of surplus electricity from the ESS can generate approximately KRW 1.7 trillion in annual sales profits, resulting in a total expected annual profit of KRW 5.3 trillion. Consequently, the investment costs, including the installation of the ESS, can be recovered in approximately six months (0.51 years).

[0083]

[0084] In the remarks column of [Table 1] above, regarding the 'Bituminous Coal Fuel Reduction Cost (D)', KRW 110.22 / kWh refers to the average annual bituminous coal fuel cost in 2022, and regarding the 'ESS Power Plant (150 MW) Estimated Construction Cost (E)', KRW 730 million / MW refers to the value when the contract price for one set of ESS equipment for system stabilization is applied, and regarding the 'Nuclear Hybrid Production Power Sales Amount (F)', KRW 52.5 / kWh refers to the nuclear power unit price in 2022.

[0085] Meanwhile, a control device according to an embodiment of the present invention can check in real time whether the surplus electricity stored in an ESS (100) or ESS battery (110) is high-voltage direct current (HVDC) that meets a predetermined standard. Through this verification process, the surplus electricity can be charged to the ESS battery (110) until the predetermined standard is met.

[0086] Here, the standard may be a voltage of 1.5 kV or higher, which is an international standard, or a voltage of 7 kV or higher, which is a Korean standard (as notified by the Ministry of Trade, Industry and Energy).

[0087] In addition, the control device according to an embodiment of the present invention can evaluate the rate of return from electricity sales in the case of transmitting electricity produced at a base power plant (10) through a transmission line (20) as alternating current (AC) and in the case of transmitting surplus electricity through a transmission line (20) as high voltage direct current (HVDC), and can determine the electricity to be transmitted to the distribution system based on the evaluation results.

[0088] For example, a transmission line (20) transmits alternating current produced at a power plant (10) during a first period of time and transmits high voltage direct current (HVDC) during a second period of time that does not overlap with the first period of time, and the first period and the second period of time can be determined based on the results of an evaluation of profitability according to electricity sales.

[0089] Since the electricity to be transmitted to the distribution system is determined by considering the profit from electricity sales in this way, profits from electricity sales can be maximized.

[0090] Meanwhile, a method for managing and controlling a hybrid power generation system according to an embodiment of the present invention will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating a method for managing a hybrid power generation and transmission system according to an embodiment of the present invention.

[0091] In step S210, the ESS installed within the base power plant stores surplus electricity generated from the base power plant.

[0092] Step S220 controls the control unit connected to the ESS to transmit surplus electricity from the ESS to the distribution grid using high-voltage direct current (HVDC) transmission technology.

[0093] At this time, surplus electricity can be transmitted from the ESS to the distribution system through transmission lines used for alternating current (AC) transmission.

[0094] That is, depending on the control of the control device, alternating current (AC) electricity produced at base power plants can be transmitted through the same transmission lines as before, or surplus electricity stored in ESS can be transmitted using high-voltage direct current (HVDC) transmission technology.

[0095] Additionally, step S220 involves evaluating the profitability of electricity sales for both AC transmission of electricity generated at baseload power plants and HVDC transmission of surplus electricity. Based on these evaluation results, the system can determine the electricity to be transmitted to the distribution system. Known calculation methods can be utilized to assess profitability.

[0096] The hybrid power generation and transmission system and its management method according to the embodiments of the present invention described so far can transmit electricity to multiple regions without installing new transmission lines or HVDC cables, thereby quickly resolving the problem of transmission line shortages. Not only in Korea but also in other countries, surplus electricity can be transmitted using ESS installed within baseload power plants and high-voltage direct current (HVDC) technology, while retaining the existing transmission lines of the power grid.

[0097] Furthermore, by utilizing high-voltage direct current (HVDC) transmission technology, embodiments of the present invention can minimize power losses that occur during alternating current (AC) transmission and transmit large amounts of power without the need for step-up and step-down processes. This maximizes the utility of existing transmission lines, and since no magnetic fields are generated, complaints about electromagnetic waves can be avoided.

[0098] The management method of a hybrid power generation and transmission system according to the above-described embodiment may be implemented as a computer program including at least one command for executing the same and stored in a computer-readable non-transitory recording medium and provided.

[0099] According to another embodiment of the present invention, a method can be implemented as computer-readable code on a medium having a program recorded thereon. Computer-readable media include all types of recording devices that store data that can be read by a computer system. Examples of computer-readable media include hard disk drives (HDDs), solid-state disk drives (SSDs), silicon disk drives (SDDs), read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices.

[0100] The foregoing description of the present invention is for illustrative purposes only. Those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0101] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims

1. In hybrid power generation and transmission systems, ESS installed in a base power plant to store surplus electricity from among the electricity produced in the base power plant; and A control device is included that controls transmission of the surplus electricity from the ESS to the distribution system using high voltage direct current (HVDC) transmission technology. A hybrid power generation and transmission system characterized in that the surplus electricity is transmitted from the ESS to the distribution system through a transmission line used for alternating current (AC) transmission.

2. In paragraph 1, The above control device A hybrid power generation and transmission system characterized in that it evaluates the profitability of electricity sales in the case of transmitting the electricity produced at the base power plant through the transmission line as alternating current (AC) and in the case of transmitting the surplus electricity through the transmission line as high-voltage direct current (HVDC), and determines the electricity to be transmitted to the distribution system based on the evaluation results.

3. In paragraph 1, A hybrid power generation and transmission system, characterized in that the control device checks in real time whether the surplus electricity stored in the ESS is high-voltage direct current (HVDC) that satisfies a predetermined standard.

4. In paragraph 3, The above-mentioned standard is a hybrid power generation and transmission system characterized by a voltage of 1.5 kV or higher according to the international standard or 7 kV or higher according to the Korean standard.

5. In the management method of hybrid power generation and transmission system, A step in which an ESS installed in a base power plant stores surplus electricity among the electricity produced in the base power plant; and A step of controlling a control device connected to the ESS to transmit the surplus electricity from the ESS to a distribution system using high-voltage direct current (HVDC) transmission technology, A management method characterized in that the above surplus electricity is transmitted from the ESS to the distribution system through a transmission line used for alternating current (AC) transmission.

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