A power system-oriented power grid accident backup configuration method

Abstract

The application provides a power grid accident backup configuration method for a new power system, and is based on the basic framework of domestic power grid defense failure set and backup capacity (including accident backup) configuration, and comprises the following steps: step S1, control area classification; step S2, failure set definition; step S3, defense failure division; step S4, backup capacity configuration; and step S5, backup configuration coordination. The application proposes the basic framework of domestic power grid defense failure set and backup capacity (including accident backup) configuration in view of the deficiencies of the existing backup configuration method, and through the clear content and requirements of the accident backup capacity configuration work, comprehensively considers the reliability, economy and regional distribution of backup capacity of the power system operation and other factors, and combines the current production practice experience to construct the backup capacity configuration method for the new power system in China, so as to guarantee the safe, stable, economic and reliable operation of the power grid.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a method for configuring grid emergency backup for power systems. Background Technology

[0002] With the development of new power systems, the operating characteristics of my country's power grid have undergone significant changes due to factors such as the continuous and rapid growth of load, the increasing penetration rate of new energy sources, and the ongoing reform of the power market. The grid faces new situations and challenges in terms of active power regulation and reserve capacity dispatch management. Specifically, load levels and the power of new energy grid connections are growing rapidly, while the installed capacity of conventional generating units is relatively insufficient. Many provinces and cities are experiencing power shortages, and there are periods of severe reserve capacity shortages, posing a significant threat to the safe operation of the power grid and reliable power supply.

[0003] By the end of 2020, my country had built a large-scale AC / DC inter-regional interconnected power grid with 30 operational ultra-high-voltage (UHV) lines (14 AC and 16 DC). UHV transmission will promote the intensive development and efficient utilization of clean energy in western and northern my country, effectively addressing issues such as power shortages, concentrated carbon emissions, and environmental pollution in eastern and central China, and ensuring electricity demand. However, at the same time, the development of the power system has gradually led to a decrease in system rotational inertia, reduced disturbance resistance, and decreased frequency regulation capability, increasing the risk of frequency stability across the entire network. This presents new challenges to the safe, reliable, and efficient operation of the power grid. For large-scale multi-DC-feeding receiving-end power grids represented by those in East China, Central China, and North China, there is a risk of high-power shortages after DC blocking, resulting in a situation with large capacity, high regional power receiving ratios, and large rated power of single-circuit DC transmission lines. The risk of high-power shortages after DC blocking becomes increasingly severe. The current requirements for safety reserves in my country's power grid are mainly derived from the "Guidelines for the Safety and Stability of Power Systems" (GB 38755-2019). It mainly uses a deterministic ratio method to determine the capacity requirements for different types of reserves, without further detailed classification and regulations based on the actual situation of power sources, loads, etc., making the operation relatively rough. Summary of the Invention

[0004] This invention proposes a power grid emergency backup configuration method for power systems. Addressing the shortcomings of existing backup configuration methods, it proposes a basic framework for configuring the fault set and backup capacity (including emergency backup) of my country's power grid. By clarifying the content and requirements of emergency backup capacity configuration, and comprehensively considering factors such as the reliability and economy of power system operation and the regional allocation of backup capacity, combined with current production practice experience, a backup capacity configuration method for my country's new power system is constructed, thereby ensuring the safe, stable, economical, and reliable operation of the power grid.

[0005] The present invention adopts the following technical solution.

[0006] A method for configuring grid contingency reserves for power systems, based on the basic architecture of domestic grid fault protection sets and reserve capacity (including contingency reserves) configuration, includes the following steps;

[0007] Step S1: Classify control areas;

[0008] Step S2: Defining the fault set;

[0009] Step S3: Arming fault classification;

[0010] Step S4: Configure standby capacity;

[0011] Step S5: Alternate configuration coordination.

[0012] The following method is used in step S1;

[0013] Synchronous power grids are divided into regional power grid control areas and provincial power grid control areas according to the hierarchy of dispatch and control authority, as follows:

[0014] Regional power grid control area: A regional power grid is an AC synchronous power grid that has the authority to configure emergency backup and dispatch control, but has no AC channel connection with other AC synchronous power grids or has an AC channel connection but no emergency backup support capability. The regional power grid consists of several provincial power control areas. Since the Yunnan power grid has no AC channel connection with other power grids, it is divided into the regional power grid control area here.

[0015] Provincial power grid control area: A synchronous AC power grid with emergency backup configuration and dispatch control authority, based on the provincial power grid, and connected to other power grids via AC channels and with emergency backup support capabilities.

[0016] Step S2 employs the following method;

[0017] Class I emergency backup protection faults are defined as: faults involved in the second level of safety and stability standards in the "Guidelines for Safety and Stability of Power Systems (GB 38755-2019)", including power loss faults of power plants connected by DC single-pole lines and single outgoing lines (including double-circuit lines on the same tower), DC faults, and complete shutdown faults of any power plant.

[0018] Class II emergency backup faults are defined as faults covered by the first-level safety and stability standards in the "Guidelines for the Safety and Stability of Power Systems (GB 38755-2019)," excluding DC unipolar line faults. The set of Class II emergency backup faults generally needs to be determined based on the specific operating conditions of the provincial power grid, and the priority of various faults should be determined according to the magnitude of the active power deficit caused by the fault.

[0019] Step S3 employs the following method;

[0020] For regional power grids, reserve emergency reserve capacity based on the maximum active power deficit that may be caused by Class I faults, and configure the ratio of spinning emergency reserve to non-spinning emergency reserve capacity.

[0021] If a regional power grid includes several provincial power grids, its reserved emergency reserve capacity must take into account the active power deficit that may be caused by a Class II defense fault.

[0022] For provincial power grids, emergency reserve capacity is reserved based on the maximum active power deficit that may be caused by Class II defense faults. The emergency reserve configuration is determined by the dispatching agency corresponding to the regional power grid.

[0023] In this example, for the provincial power grid, emergency reserve capacity is reserved based on the maximum active power deficit that may be caused by a Class II protection fault. The emergency reserve configuration principle is formulated by the dispatching agency corresponding to the regional power grid.

[0024] If there is a backup mutual assistance mechanism between different provincial power grids in a regional power grid, the backup capacity shall be reserved in accordance with the relevant agreed mechanism. In this example, the protection faults that need to be considered are shown in Table 2.

[0025] In this example, we investigated the reserve capacity configuration standards of various regions in my country and made relevant settings based on the current development status of my country's power grid.

[0026] In step S3, the active power deficit of the system caused by a Class I defense fault is set to R. i The fault types or events considered in i include DC bipolar blocking, DC unipolar blocking, and power plant (group) faults connected by a single outgoing line (including double-circuit lines on the same tower).

[0027] The active power deficit of the system caused by a Class II defense fault is set as r. i The fault types and events considered in i include DC single-pole line faults, DC single converter faults, and maximum capacity single generator faults.

[0028] The active power deficit caused by the concentrated DC bipolar blocking fault in Class I defense faults is the largest. In accordance with the "Technical Specification for Configuration of Emergency Reserve Capacity of Power System" (DL / T2238-2021), in order to ensure the safety and stability of the system and to ensure that the regional power grid emergency reserve has a certain safety margin, the regional power grid emergency reserve capacity is A as shown in the following formula.

[0029] A = MAX{R i}+r i =R1+r1 Formula 1;

[0030] In the formula, R1 is the maximum power deficit caused by the concentration of regional power grid protection faults as defined in Table 1 below, and r1 is the maximum power deficit caused by a single converter fault in the concentration of Class II protection faults in Table 2 below. The emergency reserve capacity of the regional power grid is determined by the active power deficit caused by the bipolar blocking fault in the concentration of Class I protection faults and the single converter fault in the concentration of Class II protection faults.

[0031] Table 1. Fault Set Protection Principles for Regional Power Grid Control Areas

[0032]

[0033] Table 2. Fault Set Protection Principles for Provincial Power Grid Control Areas

[0034]

[0035] The determination of the fault causing the maximum active power deficit in the provincial power grid emergency backup caused by the Class II defense fault set is based on the fact that the most serious bipolar blocking fault among DC faults has already been taken into account in the regional power grid control area. Therefore, only DC lines with a single-pole line capacity of less than 4 million kilowatts are considered in the Class II defense fault set.

[0036] The provincial power grid emergency reserve capacity B is shown in the following formula.

[0037] B = MAX{r i Formula 2.

[0038] In step S5, when selecting the backup configuration, the power deficit caused by the regional power grid failure is determined on the one hand, and the sum of the power deficits caused by the Class II failures of each provincial grid under the regional power grid is considered on the other hand.

[0039] The emergency reserve capacity under the regional power grid control area needs to cover severe faults in each provincial power grid; therefore, the sum of the emergency reserve capacities of each provincial power grid, ∑B, needs to be calculated. i Compare with the regional power grid's emergency reserve capacity A; if the sum of the emergency reserve capacities of all provincial power grids ∑B i If the regional power grid's reserve capacity configuration A is exceeded, then the regional power grid's emergency reserve capacity configuration should be updated to ∑B. i Therefore, the capacity A after coordination of the regional power grid emergency backup configuration is expressed by the following formula;

[0040] A = MAX{A, ∑B i Formula 3.

[0041] This invention provides a contingency reserve configuration method tailored to the current state of my country's power grid. It analyzes the necessity of this method under the development of new power systems, considering factors such as grid structure, receiving-end characteristics, and fault severity. Recommendations for contingency reserves in regional and provincial power grids under the new circumstances are proposed. With the continuous advancement of new power systems, the contingency reserve capacity configuration method proposed in this invention will provide a reference for the safe and efficient development of my country's power grid. Attached Figure Description

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0043] Appendix Figure 1 This is a flowchart illustrating the present invention;

[0044] Appendix Figure 2 This is a schematic diagram of the classification of regional and provincial power grid control areas. Detailed Implementation

[0045] As shown in the figure, a power grid emergency backup configuration method for power systems, based on the basic architecture of domestic power grid fault protection set and backup capacity (including emergency backup) configuration, includes the following steps;

[0046] Step S1: Classify control areas;

[0047] Step S2: Defining the fault set;

[0048] Step S3: Arming fault classification;

[0049] Step S4: Configure standby capacity;

[0050] Step S5: Alternate configuration coordination.

[0051] The following method is used in step S1;

[0052] Synchronous power grids are divided into regional power grid control areas and provincial power grid control areas according to the hierarchy of dispatch and control authority, such as... Figure 2 As shown, specifically:

[0053] Regional power grid control area: A regional power grid is an AC synchronous power grid that has the authority to configure emergency backup and dispatch control, but has no AC channel connection with other AC synchronous power grids or has an AC channel connection but no emergency backup support capability. The regional power grid consists of several provincial power control areas. Since the Yunnan power grid has no AC channel connection with other power grids, it is divided into the regional power grid control area here.

[0054] Provincial power grid control area: A synchronous AC power grid with emergency backup configuration and dispatch control authority, based on the provincial power grid, and connected to other power grids via AC channels and with emergency backup support capabilities.

[0055] Step S2 employs the following method;

[0056] Class I emergency backup protection faults are defined as: faults involved in the second level of safety and stability standards in the "Guidelines for Safety and Stability of Power Systems (GB 38755-2019)", including power loss faults of power plants connected by DC single-pole lines and single outgoing lines (including double-circuit lines on the same tower), DC faults, and complete shutdown faults of any power plant.

[0057] Class II emergency backup faults are defined as faults covered by the first-level safety and stability standards in the "Guidelines for the Safety and Stability of Power Systems (GB 38755-2019)," excluding DC unipolar line faults. The set of Class II emergency backup faults generally needs to be determined based on the specific operating conditions of the provincial power grid, and the priority of various faults should be determined according to the magnitude of the active power deficit caused by the fault.

[0058] Step S3 employs the following method;

[0059] For regional power grids, reserve emergency reserve capacity based on the maximum active power deficit that may be caused by Class I faults, and configure the ratio of spinning emergency reserve to non-spinning emergency reserve capacity.

[0060] If a regional power grid includes several provincial power grids, its reserved emergency reserve capacity must take into account the active power deficit that may be caused by a Class II defense fault.

[0061] For provincial power grids, emergency reserve capacity is reserved based on the maximum active power deficit that may be caused by Class II defense faults. The emergency reserve configuration is determined by the dispatching agency corresponding to the regional power grid.

[0062] Where there is a backup mutual assistance mechanism between different provincial power grids in a regional power grid, the reserve capacity shall be reserved in accordance with the relevant agreed mechanism.

[0063] In step S3, the active power deficit of the system caused by a Class I defense fault is set to R. i The fault types or events considered in i include DC bipolar blocking, DC unipolar blocking, and power plant (group) faults connected by a single outgoing line (including double-circuit lines on the same tower).

[0064] The active power deficit of the system caused by a Class II defense fault is set as r. i The fault types and events considered in i include DC single-pole line faults, DC single converter faults, and maximum capacity single generator faults.

[0065] The active power deficit caused by the concentrated DC bipolar blocking fault in Class I defense faults is the largest. In accordance with the "Technical Specification for Configuration of Emergency Reserve Capacity of Power System" (DL / T2238-2021), in order to ensure the safety and stability of the system and to ensure that the regional power grid emergency reserve has a certain safety margin, the regional power grid emergency reserve capacity is A as shown in the following formula.

[0066] A = MAX{R i}+r i =R1+r1 Formula 1;

[0067] In the formula, R1 is the maximum power deficit caused by the concentration of regional power grid protection faults as defined in Table 1 below, and r1 is the maximum power deficit caused by a single converter fault in the concentration of Class II protection faults in Table 2 below. The emergency reserve capacity of the regional power grid is determined by the active power deficit caused by the bipolar blocking fault in the concentration of Class I protection faults and the single converter fault in the concentration of Class II protection faults.

[0068] Table 1. Fault Set Protection Principles for Regional Power Grid Control Areas

[0069]

[0070] Table 2. Fault Set Protection Principles for Provincial Power Grid Control Areas

[0071]

[0072] The determination of the fault causing the maximum active power deficit in the provincial power grid emergency backup caused by the Class II defense fault set is based on the fact that the most serious bipolar blocking fault among DC faults has already been taken into account in the regional power grid control area. Therefore, only DC lines with a single-pole line capacity of less than 4 million kilowatts are considered in the Class II defense fault set.

[0073] The provincial power grid emergency reserve capacity B is shown in the following formula.

[0074] B = MAX{r i Formula 2.

[0075] In step S5, when selecting the backup configuration, the power deficit caused by the regional power grid failure is determined on the one hand, and the sum of the power deficits caused by the Class II failures of each provincial grid under the regional power grid is considered on the other hand.

[0076] The emergency reserve capacity under the regional power grid control area needs to cover severe faults in each provincial power grid; therefore, the sum of the emergency reserve capacities of each provincial power grid, ∑B, needs to be calculated. i Compare with the regional power grid's emergency reserve capacity A; if the sum of the emergency reserve capacities of all provincial power grids ∑B i If the regional power grid's reserve capacity configuration A is exceeded, then the regional power grid's emergency reserve capacity configuration should be updated to ∑B. iTherefore, the capacity A after coordination of the regional power grid emergency backup configuration is expressed by the following formula;

[0077] A = MAX{A, ΣB i Formula 3.

[0078] Example:

[0079] This embodiment uses data from the East China Power Grid in 2020 as an example to illustrate the implementation steps of a fault reserve configuration method for my country's new power system.

[0080] (1) Classification of Control Zones

[0081] Due to differences in dispatch control authority, the East China Power Grid belongs to the regional power grid control area, while Shanghai, Zhejiang, Jiangsu, Anhui, and Fujian belong to the provincial power grid control areas.

[0082] (2) Fault set definition

[0083] Category I emergency backup protection faults include power loss faults at power plants connected to a single DC line or a single outgoing line (including double-circuit lines on the same tower), DC faults, and complete shutdowns of any power plant. Category II emergency backup protection faults include DC line faults, DC converter faults, and faults of the largest single generator.

[0084] (3) Fault classification

[0085] Based on the 2020 load data and 2022 renewable energy data, the results of the Class I and Class II fault protection sets were compiled. Class I fault protection sets comprehensively consider three fault protection principles: DC single-pole and double-pole blocking faults, and power loss at power plants (groups) connected to a single transmission line (including double-circuit lines on the same tower). Class II emergency standby fault protection sets consider three fault protection principles: DC line faults, DC converter faults, and faults of the largest single generator. For the East China Power Grid, the maximum active power deficit in the Class I fault protection set is determined by the DC double-pole blocking fault protection set, therefore the maximum active power deficit in the East China Power Grid is 12 million kilowatts. The maximum active power deficit in the Class II fault protection set of the East China Power Grid is determined by the DC single-pole line fault protection set, and the maximum active power deficit in the provincial power grids of East China is 4 million kilowatts.

[0086] (4) Emergency reserve capacity configuration of East China Power Grid and provincial power grids

[0087] The emergency reserve capacity of power grids in various regions of my country is the sum of the active power deficit caused by bipolar blocking faults (Category I) and single converter faults (Category II), as shown in Table 3. The emergency reserve capacity A of the East China power grid is 14 million kilowatts.

[0088] Table 3 Regional Power Grid Emergency Backup Capacity (Unit: 10,000 kW)

[0089]

[0090] This configuration method recommends that the emergency reserve capacity of each provincial power grid be selected from the larger value between DC single converter faults and the largest capacity generator faults in the province's Class II fault protection set, as shown in the following formula.

[0091] B = Max{r1, r2} (4)

[0092] In the formula, r1 and r2 represent the power deficit caused by provincial power grid faults. Taking the East China Power Grid as an example, the emergency reserve capacity of each provincial power grid is shown in Table 4. The emergency reserve capacity of Shanghai power grid is 1.6 million kilowatts, that of Jiangsu power grid is 2.5 million kilowatts, that of Zhejiang power grid is 2 million kilowatts, that of Anhui power grid is 3 million kilowatts, and that of Fujian power grid is 1.2 million kilowatts.

[0093] Table 4. Emergency standby capacity of each province in the East China Power Grid (Unit: 10,000 kilowatts)

[0094]

[0095] (5) Backup configuration coordination

[0096] To ensure the safe and reliable operation of the power grid, the emergency reserve capacity of the regional power grid must also cover severe faults in the provincial power grids. Therefore, it is necessary to sum the emergency reserve capacities of the provincial power grids, ∑B. i Compare with the emergency reserve capacity A of the East China Power Grid.

[0097] ∑B i =160+250+200+300+120=1030 (5) In formula (3), the sum of the emergency reserve capacity of each provincial power grid in East China is less than the emergency reserve configuration capacity of East China Power Grid, so the emergency capacity configuration of East China Power Grid is selected as 14 million kilowatts.

Claims

1. A power system-oriented power grid contingency reserve configuration method based on the basic framework of domestic power grid defense failure set and reserve capacity configuration, wherein the reserve capacity configuration includes contingency reserve configuration, characterized in that it comprises the following steps: Step S1, control area classification; Step S2, failure set definition; Step S3, defense failure division; Step S4, reserve capacity configuration; Step S5, reserve configuration coordination; The step S1 adopts the following method: Synchronous power grids are divided into regional power grid control areas and provincial power grid control areas according to the scheduling control authority level, specifically: Regional power grid control area: taking regional power grid as a unit, with contingency reserve configuration scheduling control authority, and no exchange channel connection with other AC synchronous power grids or exchange channel connection but no contingency reserve support capability of AC synchronous power grids; the regional power grid is composed of several provincial power control areas, and since the Yunnan power grid has no exchange channel with other power grids, it is divided into a regional power grid control area; Provincial power grid control area: taking provincial power grid as a unit, with contingency reserve configuration scheduling control authority, and with exchange channel connection with other power grids and with contingency reserve support capability of AC synchronous power grids; The step S2 adopts the following method: Define the I-class defense failure set as: the failure involved in the second level safety and stability standard in the power system safety and stability guide GB 38755-2019, including DC single-pole line, single transmission line connected power plant power loss failure, DC fault and any power plant total stop failure, wherein the single transmission line includes same tower double circuit line; Define the II-class defense failure set as: the failure involved in the first level safety and stability standard in the power system safety and stability guide GB 38755-2019 except the DC single-pole line failure; the II-class defense failure set needs to be determined based on the specific operation of the provincial power grid, and the priority order of each type of failure is determined according to the active power shortage caused by the failure; The step S3 adopts the following method: For regional power grid, reserve contingency reserve capacity according to the maximum active power shortage caused by I-class defense failure, and configure the proportion of rotating contingency reserve and non-rotating contingency reserve capacity; If the regional power grid contains several provincial power grids, the reserved contingency reserve capacity needs to consider the active power shortage caused by II-class defense failure; For provincial power grid, reserve contingency reserve capacity according to the maximum active power shortage caused by II-class defense failure, and the contingency reserve configuration is formulated by the dispatching institution corresponding to the regional power grid; If there is a reserve mutual aid mechanism between different provincial power grids in the regional power grid, reserve capacity is left according to the relevant agreement mechanism; The maximum active power shortage caused by the DC bipolar blocking failure in the I-class defense failure set, combined with the power system contingency reserve capacity configuration technical specification DL / T 2238-2021, in order to ensure the safety and stability of the system, and ensure that the regional power grid contingency reserve has a certain safety margin, the regional power grid contingency reserve capacity is A as shown in the following formula: In step S3, the active power deficiency amount R caused by the Class I protection fault is set i where i includes fault types or events considered, such as DC bipolar blocking, DC single pole blocking, and single transmission line connected power plant fault, where the single transmission line includes a double circuit line in the same tower; The active deficiency of the system caused by a fault of class II is denoted by r i where i includes the fault types and events considered: DC single line fault, DC single converter fault, maximum capacity single generator fault.

2. The power system oriented method for configuration of contingency reserves for power grid according to claim 1, characterized in that: ​ A = MAX{R i} + r i = R1 + r1 Equation One; Wherein, R1 is the maximum power shortage caused by the regional power grid defense fault set principle defined in Table 1 below, r1 is the maximum power shortage caused by the single converter fault in the II type defense fault set principle in Table 2 below, and the regional power grid emergency reserve capacity is determined by the active power shortage caused by the bipolar blocking fault in the I type accident defense fault set and the single converter fault in the II type accident defense fault set; Table 1: Regional power grid control area defense fault set principle Table 2. Provincial power grid control area defense fault set principle The provincial power grid emergency reserve is determined by the maximum active power shortage caused by the fault in the II type defense fault set. Since the most serious bipolar blocking fault in the DC fault has been considered in the regional power grid control area, only the DC with a single-pole line capacity of less than 4 million kilowatts is considered in the II type defense fault set; The provincial power grid emergency reserve capacity is B shown in the following formula B = MAX{r i} Equation Two.

3. The power system oriented method of configuring a backup for grid contingencies according to claim 1, characterized in that: Step S5 in selecting the reserve configuration, on the one hand, the power shortage caused by the regional power grid defense fault is determined, and on the other hand, the sum of the power shortage caused by the II type defense fault of each provincial grid under the regional power grid is considered. The accident backup capacity under the regional power grid control area needs to cover the serious failure of each provincial power grid, so the sum of the accident backup capacity of each provincial power grid ∑B i is compared with the regional power grid accident backup capacity A; if the sum of the accident backup capacity of each provincial power grid ∑B i exceeds the regional power grid backup configuration capacity A, the regional power grid accident backup capacity configuration should be updated to ∑B i , so the coordinated capacity A of the regional power grid accident backup configuration is expressed by the formula as follows; A = MAX{A,∑B i} Equation Three.

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