Inertia safety assessment method and device for power system

Abstract

The invention is suitable for the technical field of power systems, and provides a power system inertia safety assessment method and device. The method comprises the following steps: acquiring voltage data, current data and frequency of each node in a power system at the same time; wherein the node corresponds to a generator or load equipment in the power system; determining the system overall inertia of the power system based on the voltage data, the current data and the frequency of each node; acquiring a plurality of system inertia safety boundary values; the plurality of system inertia safety boundary values are determined according to a plurality of levels of fault data in a preset fault set, and the preset fault set is determined according to the power system; and determining the safety state of the overall inertia of the system according to the overall inertia of the system and the plurality of system inertia safety boundary values. According to the method and the device, the overall inertia of the system can be accurately determined, and accurate safety evaluation on the overall inertia of the system is realized based on the plurality of system inertia safety boundary values to obtain the safety state, so that related personnel can formulate prevention measures according to the safety state.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a method and device for safety assessment of inertia of a power system. Background Art

[0002] In a high-penetration new energy power system, a high proportion of new energy equipment is connected to the grid and replaces the original synchronous machine, resulting in a decrease in the inertia level of the power system, affecting the safe and stable operation of the power system. In addition, the access of different types of sources and loads to the grid also complicates the inertia structure of the power system. The inertia of the power system is an important indicator for measuring the stability of the power system. Accurately determining the inertia of the power system (that is, the overall inertia of the system) and conducting a safety assessment so that the power system can be reasonably dispatched and maintained based on the assessment results is of great significance to the stable operation of the power system.

[0003] At present, in the process of determining the inertia of the power system, the parameters and processing methods used to determine the inertia of the power system are relatively rigid, and it is impossible to process data flexibly and effectively, and thus it is impossible to accurately determine the inertia of the power system. In addition, there is also a lack of a complete system in the relevant technology to conduct a safety assessment of the inertia of the power system, which ultimately leads to the inability to accurately determine the inertia of the power system and conduct an accurate safety assessment. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a method and device for safety assessment of inertia of a power system to solve the technical problem in the related art that it is impossible to accurately determine the inertia of the power system and perform accurate safety assessment.

[0005] In a first aspect, an embodiment of the present application provides a method for safety assessment of inertia of a power system, comprising:

[0006] Obtain voltage data, current data and frequency of each node in the power system at the same time; where the node corresponds to a generator or load device in the power system;

[0007] Determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node;

[0008] Acquire multiple system inertia safety boundary values; the multiple system inertia safety boundary values ​​are determined according to multiple levels of fault data in a preset fault set, and the preset fault set is determined according to the power system;

[0009] A safe state of the system overall inertia is determined according to the system overall inertia and the plurality of system inertia safety boundary values.

[0010] In a possible implementation, the fault data includes the maximum disturbance power, the fault loss, the maximum frequency change rate limit and the frequency shortage limit allowed by the system; each level of fault data corresponds to each system inertia safety boundary value one by one;

[0011] The method further comprises:

[0012] For each level, determine the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss and maximum frequency change rate limit of the level;

[0013] Determine the second minimum inertia requirement corresponding to the level according to the maximum disturbance power of the level, the fault loss amount and the frequency deficiency limit allowed by the system;

[0014] A system inertia safety boundary value corresponding to the level is determined based on a maximum value between the first minimum inertia requirement and the second minimum inertia requirement.

[0015] In a possible implementation, the preset fault set includes a DC blocking fault set and a power tripping fault set;

[0016] For each level, determining the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level includes:

[0017] For each level, determine whether the maximum disturbance power of the level in the DC blocking fault set is greater than or equal to the maximum disturbance power of the level in the power tripping fault set;

[0018] If the maximum disturbance power of this level in the DC blocking fault set is greater than or equal to the maximum disturbance power of this level in the power tripping fault set, then the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the DC blocking fault set;

[0019] If the maximum disturbance power of this level in the DC locking type fault set is less than the maximum disturbance power of this level in the power tripping type fault set, the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the power tripping type fault set.

[0020] In a possible implementation, the node includes a generator node, and the generator node corresponds to a generator in the power system; the voltage data includes a voltage amplitude and a voltage phase angle, and the current data includes a current amplitude and a current phase angle;

[0021] The determining the overall system inertia of the power system based on the voltage data, current data and frequency of each node includes:

[0022] Determine the active power of each node according to the voltage amplitude, voltage phase angle, current amplitude and current phase angle of each node;

[0023] Determining a frequency change rate of each node according to the frequency of each node;

[0024] Based on the active power and frequency change rate of each node, the overall system inertia time constant of the power system is obtained;

[0025] The overall inertia of the system is obtained according to the sum of the overall inertia time constant of the system and the capacity of the generator of each generator node.

[0026] In a possible implementation, the multiple levels include a first level, a second level, and a third level with fault severity increasing in sequence; the multiple system inertia safety boundary values ​​include a first safety boundary value, a second safety boundary value, and a third safety boundary value with values ​​increasing in sequence; the safety state includes an unsafe state, a critical safety state, a relatively safe state, and an absolutely safe state with safety levels increasing in sequence;

[0027] Determining the safety state of the overall inertia of the system according to the overall inertia of the system and the plurality of system inertia safety boundary values ​​includes:

[0028] If the overall inertia of the system is less than or equal to the first safety boundary value, determining that the safety state of the overall inertia of the system is an unsafe state;

[0029] If the overall inertia of the system is greater than the first safety boundary value and less than or equal to the second safety boundary value, determining that the safety state of the overall inertia of the system is a critical safety state;

[0030] If the overall inertia of the system is greater than the second safety boundary value and less than or equal to the third safety boundary value, determining that the safety state of the overall inertia of the system is a relatively safe state;

[0031] If the overall inertia of the system is greater than the third safety boundary value, it is determined that the safety state of the overall inertia of the system is an absolute safety state.

[0032] In a possible implementation, the node includes a generator node, and the generator node corresponds to a generator in the power system;

[0033] For each level, determining the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level includes:

[0034] For each level, according to the maximum disturbance power, fault loss, maximum frequency change rate limit and the first formula

[0035] Determine the first minimum inertia requirement corresponding to the level;

[0036] In the formula, is the first minimum inertia requirement, ΔP max is the maximum disturbance power, R oCoF,limit is the maximum frequency change rate limit, H ls is the failure loss, S i is the capacity of the generator of the i-th generator node, and n is determined according to the number of generator nodes.

[0037] In a possible implementation, for each level, determining the second minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and frequency deficiency limit allowed by the system of the level includes:

[0038] According to the maximum disturbance power of this level, the amount of fault loss, the frequency deficiency limit allowed by the system and the second formula

[0039] Determine the second minimum inertia requirement corresponding to the level;

[0040] In the formula, is the second minimum inertia requirement, f N is the rated frequency of the power system, D is the damping coefficient of the power system, f limit is the frequency limit allowed by the power system, f limit =Δf limit -f N , Δf limit is the frequency deficiency limit allowed by the power system, f db is the dead zone frequency, R SYS It is the primary frequency regulation response rate of the power system.

[0041] In a possible implementation, the expression of the system inertia safety boundary value is:

[0042]

[0043] In the formula, E sc is the safety boundary value of system inertia.

[0044] In a second aspect, an embodiment of the present application provides a power system inertia safety assessment device, comprising:

[0045] The first acquisition module is used to acquire voltage data, current data and frequency of each node in the power system at the same time; wherein the node corresponds to a generator or load device in the power system;

[0046] A first determination module, configured to determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node;

[0047] A second acquisition module is used to acquire a plurality of system inertia safety boundary values; the plurality of system inertia safety boundary values ​​are determined according to fault data of a plurality of levels in a preset fault set, and the preset fault set is determined according to the power system;

[0048] The second determination module is used to determine the safety state of the overall inertia of the system according to the overall inertia of the system and the multiple system inertia safety boundary values.

[0049] In a possible implementation, the fault data includes the maximum disturbance power, the fault loss, the maximum frequency change rate limit and the frequency shortage limit allowed by the system; each level of fault data corresponds to each system inertia safety boundary value one by one;

[0050] The second acquisition module is also used to determine, for each level, a first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level; determine a second minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and frequency shortage limit allowed by the system; and determine the system inertia safety boundary value corresponding to the level based on the maximum value of the first minimum inertia requirement and the second minimum inertia requirement.

[0051] It can be understood that the beneficial effects of the second aspect mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0052] The power system inertia safety assessment method and device provided in the embodiment of the present application can accurately determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node in the power system at the same time, and then, based on the overall system inertia and multiple system inertia safety boundary values, perform a safety assessment on the overall system inertia to determine the safety state of the overall system inertia, wherein multiple system inertia safety boundary values ​​are determined based on multiple levels of fault data in a preset fault set, and the obtained multiple system inertia safety boundary values ​​are used to perform an accurate safety assessment on the overall system inertia. The embodiment of the present application can accurately determine the overall system inertia and multiple system inertia safety boundary values, thereby achieving an accurate safety assessment of the overall system inertia, and obtaining the safety state of the overall system inertia, so that relevant personnel can formulate preventive measures according to the safety state.

[0053] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0055] Figure 1 It is a schematic diagram of an application scenario provided by an embodiment of the present application;

[0056] Figure 2 It is a flowchart of a method for safety assessment of inertia of a power system provided in one embodiment of the present application;

[0057] Figure 3 It is a schematic diagram of the correspondence between multiple system inertia safety boundary values ​​and multiple levels of fault data provided by an embodiment of the present application;

[0058] Figure 4 It is a schematic diagram of the corresponding relationship between the system inertia safety boundary value and the inertia safety factor provided in an embodiment of the present application;

[0059] Figure 5 It is a structural schematic diagram of a power system inertia safety assessment device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0060] The present application is described more clearly below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the effects of the present application, but are not intended to limit the present application in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present application. These all fall within the scope of protection of the present application.

[0061] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0062] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0063] In the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0064] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0065] In addition, the “plurality” mentioned in the embodiments of the present application should be interpreted as two or more.

[0066] With the idea of ​​accurately determining the inertia of the power system and accurately conducting a safety assessment of the inertia of the power system, the inventor has discovered through research that the overall system inertia of the power system can be accurately determined based on the relevant data of each node in the power system at the same time. Then, based on the overall inertia of the system and multiple system inertia safety boundary values, the overall system inertia is safety assessed to determine the safety state, wherein the multiple system inertia safety boundary values ​​are determined based on multiple levels of fault data in a preset fault set, and can be used to conduct an accurate safety assessment of the overall system inertia.

[0067] At the same time, the inventors also applied situational awareness technology, guided by situational awareness, situational understanding and situational guidance, to provide a new idea for the safety assessment of the overall inertia of the system, and formed a logically rigorous framework and system to conduct a safety assessment of the overall inertia of the system.

[0068] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific embodiments will be described below in conjunction with the accompanying drawings.

[0069] First reference Figure 1 , Figure 1 The application scenario of the present application is schematically shown. In the application scenario, an electronic device 101 and a plurality of synchronized phasor measurement devices 102 are included. Each synchronized phasor measurement device 102 can be installed on each node required to be measured.

[0070] The measurement transmitter of each synchronous phasor measurement device 102 respectively obtains the voltage data, current data and frequency of each node in the power system at the same time, and sends the above data to the electronic device 101. After the electronic device 101 obtains the voltage data, current data and frequency of each node in the power system at the same time, it determines the overall system inertia of the power system based on the voltage data, current data and frequency of each node, and determines the safety state of the overall system inertia according to the above overall system inertia and the obtained multiple system inertia safety boundary values. Among them, the multiple system inertia safety boundary values ​​are determined according to multiple levels of fault data in a preset fault set, and the preset fault set is determined according to the power system.

[0071] The electronic device 101 communicates with the synchronized phasor measurement device 102 by wireless or wired means, and each synchronized phasor measurement device 102 can be arranged at the grid connection point of each node in the power system. The synchronized phasor measurement device 102 is a phasor measurement unit that uses the global positioning system second pulse as a synchronous clock and can be easily installed on the required measurement node.

[0072] Combine the following Figure 1 ,refer to Figure 2 To describe the power system inertia safety assessment method provided according to an exemplary embodiment of the present application.

[0073] Figure 2 It is a flow chart of a method for safety assessment of inertia of a power system provided in one embodiment of the present application.

[0074] like Figure 2 As shown, the method in the embodiment of the present application may include:

[0075] Step 201: Obtain voltage data, current data and frequency of each node in the power system at the same time.

[0076] In this embodiment, the node corresponds to a generator or load device in the power system. Accordingly, the node includes a generator node and a load node. For example, if the power system includes n generators and m load devices, the node includes n generator nodes and m load nodes. Each node in the power system is in operation. The voltage data includes voltage amplitude and voltage phase angle, and the current data includes current amplitude and current phase angle.

[0077] Here, as mentioned earlier, in view of the randomness, volatility and intermittency of distributed power sources in nodes, real-time dynamic measurement using synchronous measurement technology can realize real-time monitoring of the operating status of the power system. In view of the multi-faceted and wide-ranging characteristics of distributed power sources, the phase and data synchronization of synchronous measurement technology can realize wide-area and simultaneous inertia partition analysis.

[0078] Step 202: Determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node.

[0079] In some embodiments, when determining the overall system inertia of the power system, the active power of each node can be determined based on the voltage amplitude, voltage phase angle, current amplitude and current phase angle of each node, and the frequency change rate of each node can be determined based on the frequency of each node. Then, based on the active power and frequency change rate of each node, the overall system inertia time constant of the power system is obtained, and the overall system inertia is obtained based on the sum of the system overall inertia time constant and the capacity of the generator of each generator node.

[0080] Optionally, the expression for active power is:

[0081]

[0082] In the formula, P is the active power, U is m is the voltage amplitude, is the voltage phase angle, I m is the current amplitude, is the current phase angle.

[0083] Exemplarily, in this embodiment, the frequency change rate of each node is calculated based on the frequency of each node and the frequency of each node at the previous moment. Afterwards, when determining the inertia time constant, considering that the angular velocity of the magnetic field inside the generator is difficult to measure and it is difficult to obtain the inertia time constant of a single generator, this embodiment treats the power system as a large generator and obtains the rotor motion equation generalized from the rotor motion equation of a single generator to the rotor motion equation of the entire power system:

[0084]

[0085] Where T is the overall inertia time constant of the power system, is the overall frequency change rate of the power system, P G is the sum of the active powers corresponding to all generator nodes in the power system, P L is the sum of the active powers corresponding to all load nodes, that is, the total power consumed by the load equipment in the power system, D is the damping coefficient of the power system, f N is the rated frequency of the power system, and f is the actual frequency of the power system, which is the sum of the frequencies of all nodes.

[0086] Here, considering the relationship between the inertia time constant of a single generator and the overall inertia time constant of the system, as well as the relationship between the damping coefficient of a single generator and the damping coefficient of the power system, that is, the inertia time constant of the ith generator is proportional to its capacity and inversely proportional to the overall inertia time constant of the system, and the damping coefficient of the ith generator is proportional to its capacity and inversely proportional to the overall inertia time constant of the system. Then, the overall inertia time constant of the system and the damping coefficient of the power system are weighted respectively, and the following expansion formula is obtained:

[0087]

[0088] In the formula, S i is the capacity of the generator of the i-th generator node, i = 1, 2, ..., n, n is determined according to the number of generator nodes, is the frequency change rate of the nth generator node, P Gn is the active power of the nth generator node, P Lm is the active power of the mth load node, m is determined according to the number of load nodes, f n is the frequency of the nth generator node. Among them, [] T Indicates transpose.

[0089] In this way, according to the active power of each node, the frequency change rate of each generator node, the frequency of each generator node, and the above expansion formula, the overall inertia time constant of the power system can be obtained. Then, according to the sum of the overall inertia time constant of the system and the capacity of the generator of each generator node, the overall inertia of the system is obtained.

[0090] The expression for the overall inertia of the system is:

[0091]

[0092] In this embodiment, since the voltage amplitude, voltage phase angle, current amplitude, current phase angle and frequency of each node are data at the same time and there is no time difference, the overall inertia of the system obtained based on the above data at the same time is accurate.

[0093] Step 203 , obtaining a plurality of system inertia safety boundary values; the plurality of system inertia safety boundary values ​​are determined according to fault data of a plurality of levels in a preset fault set, and the preset fault set is determined according to the power system.

[0094] Since the level of power system inertia directly affects the stability of the power system after a large disturbance, in this embodiment, after determining the overall system inertia, a safety assessment of the overall system inertia is performed, that is, the safety status of the overall system inertia is determined, so that relevant personnel can formulate preventive measures based on the safety status, providing an effective basis for the optimal configuration of inertia resources.

[0095] It is known that the safety and stability standards for the power system's ability to withstand disturbances stipulated by the state are divided into three levels. Accordingly, there are "three lines of defense" for the power system to ensure the safe and stable operation of the power system when encountering various accidents. In order to accurately conduct a safety assessment of the overall inertia of the system, this application is based on the "three lines of defense" of the power system to construct a fault set including fault data of different levels, so as to determine the safety boundary values ​​of the inertia of each system corresponding to each line of defense according to the fault set, and conduct a safety assessment of the overall inertia of the system.

[0096] Exemplarily, multiple system inertia safety boundary values ​​are determined based on multiple levels of fault data in a preset fault set, and each level of fault data corresponds to each system inertia safety boundary value. The fault data includes the maximum disturbance power, the fault loss, the maximum frequency change rate limit, and the frequency shortage limit allowed by the system.

[0097] Optionally, in this embodiment, the fault set is constructed based on the planning data and construction data of the power system. For example, the planning data and construction data may include the power system topology, the rated output of the generator, the minimum output of the generator, and the DC feed-in power and output power, the power system load, the power supply and the DC operation status, etc. As can be seen from the foregoing, each level of fault data corresponds one-to-one to each system inertia safety boundary value, that is, one-to-one to each defense line of the power system. When constructing a data set and determining each level of fault data in the data set, this embodiment determines the level of fault data corresponding to each defense line based on the planning data and construction data of the power system under the defense line. For example, a fault simulation can be performed based on the planning data and construction data of the power system under the defense line to obtain the level of fault data corresponding to the defense line.

[0098] In a possible implementation manner, this embodiment may further include steps A1 to A3.

[0099] A1. For each level, determine the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss and maximum frequency change rate limit of the level.

[0100] A2. Determine the second minimum inertia requirement corresponding to this level based on the maximum disturbance power, fault loss and frequency deficiency limit allowed by the system.

[0101] A3. Determine the system inertia safety boundary value corresponding to the level based on the maximum value of the first minimum inertia requirement and the second minimum inertia requirement.

[0102] In some embodiments, for each level, the maximum disturbance power, fault loss, maximum frequency change rate limit and the first formula of the level can be used to calculate the maximum disturbance power, fault loss, maximum frequency change rate limit and the first formula of the level.

[0103] Determine the first minimum inertia requirement corresponding to this level.

[0104] In the formula, is the first minimum inertia requirement, ΔP max is the maximum disturbance power, R oCoF,limit is the maximum frequency change rate limit, H ls is the failure loss, S i is the capacity of the generator of the i-th generator node, and n is determined according to the number of generator nodes.

[0105] In some embodiments, for each level, the maximum disturbance power of the level, the fault loss amount, the frequency shortage limit allowed by the system and the second formula

[0106]

[0107] 2. Minimum inertia requirement.

[0108] In the formula, is the second minimum inertia requirement, f N is the rated frequency of the power system, D is the damping coefficient of the power system, f limit is the frequency limit allowed by the power system, f limit =Δf limit -f N , Δf limit is the frequency deficiency limit allowed by the power system, f db is the dead zone frequency, R SYS It is the primary frequency regulation response rate of the power system.

[0109] The expression of the system inertia safety boundary value is:

[0110]

[0111] In the formula, E sc is the safety boundary value of system inertia.

[0112] Here, the first minimum inertia requirement is determined based on the maximum frequency change rate limit of the power system, and the second minimum inertia requirement is determined based on the frequency shortage limit allowed by the power system. That is, the system inertia safety boundary value is determined based on the two key indicators of the maximum frequency change rate limit and the frequency shortage limit allowed by the power system, and the system inertia safety boundary value can be accurately obtained.

[0113] In this way, for each level, this embodiment can calculate the system inertia safety boundary value corresponding to the level based on the fault data of the level, thereby obtaining multiple system inertia safety boundary values ​​corresponding to the "three lines of defense" of the power system, so as to determine the safety state of the overall system inertia.

[0114] Exemplarily, in this embodiment, corresponding to the "three lines of defense" of the power system, the multiple levels may include the first level, the second level, and the third level with increasing fault severity, the multiple system inertia safety boundary values ​​may include the first safety boundary value, the second safety boundary value, and the third safety boundary value with increasing values, and the safety state may include the unsafe state, the critical safety state, the relatively safe state, and the absolutely safe state with increasing safety levels. Among them, the first safety boundary value corresponds to the first line of defense of the power system, the second safety boundary value corresponds to the second line of defense, and the third safety boundary value corresponds to the third line of defense.

[0115] It should be noted that the preset fault set may include a DC blocking fault set and a power tripping fault set. The DC blocking fault includes a single-pole blocking fault, and the power tripping fault includes a single generator fault and a multi-generator fault. Figure 3 As shown, the DC locking type fault set includes fault data of the first level to the third level, and the power tripping type fault set also includes fault data of the first level to the third level. As mentioned above, the first level corresponds to the first safety boundary value and corresponds to the first line of defense of the power system, the second level corresponds to the second safety boundary value and corresponds to the second line of defense, and the third level corresponds to the third safety boundary value and corresponds to the third line of defense.

[0116] When the minimum inertia requirement is subsequently calculated for each level, it can be determined whether to determine the minimum inertia requirement based on a DC blocking type fault set or a power tripping type fault set according to the maximum disturbance power in the fault data.

[0117] In a possible implementation manner, for each level, when determining the first minimum inertia requirement corresponding to the level, this embodiment can determine, for each level, whether the maximum disturbance power of the level in the DC locking type fault set is greater than or equal to the maximum disturbance power of the level in the power tripping type fault set; if the maximum disturbance power of the level in the DC locking type fault set is greater than or equal to the maximum disturbance power of the level in the power tripping type fault set, then the first minimum inertia requirement corresponding to the level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the DC locking type fault set; otherwise, the first minimum inertia requirement corresponding to the level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the power tripping type fault set.

[0118] It should be noted that, for each level, when determining the second minimum inertia requirement corresponding to the level, this embodiment also determines whether to obtain the second minimum inertia requirement according to the DC locking type fault set or the power tripping type fault set based on the maximum disturbance power. The specific implementation process and principles can refer to the relevant description of determining the first minimum inertia requirement corresponding to the level in the above embodiment, which will not be repeated here.

[0119] Step 204: Determine the safety state of the system's overall inertia according to the system's overall inertia and a plurality of system inertia safety boundary values.

[0120] In some embodiments, when determining the safe state of the overall inertia of the system, steps B1 to B4 may be included.

[0121] B1. If the overall inertia of the system is less than or equal to the first safety boundary value, it is determined that the safety state of the overall inertia of the system is an unsafe state.

[0122] B2. If the overall inertia of the system is greater than the first safety boundary value and less than or equal to the second safety boundary value, it is determined that the safety state of the overall inertia of the system is a critical safety state.

[0123] B3. If the overall inertia of the system is greater than the second safety boundary value and less than or equal to the third safety boundary value, it is determined that the safety state of the overall inertia of the system is a relatively safe state.

[0124] B4. If the overall inertia of the system is greater than the third safety boundary value, the safety state of the overall inertia of the system is determined to be an absolute safety state.

[0125] Exemplarily, this embodiment performs a safety assessment on the overall inertia of the system and determines the safety status of the overall inertia of the system so that relevant personnel can formulate defense measures or implement corresponding measures according to the obtained safety status.

[0126] For example, when it is determined that the safety state of the system's overall inertia is an unsafe state, an unsafe alarm prompt can be issued to enable relevant personnel to take corresponding measures to improve the inertia level of the power system, such as adding a frequency auxiliary control function for new energy sources and limiting the minimum startup scale of the system's synchronous power supply. When it is determined that the safety state of the system's overall inertia is a critical safety state, a critical safety alarm prompt can be issued to remind relevant personnel to pay attention to changes in the inertia level of the power system and to formulate corresponding measures in advance to prevent the system's overall inertia from entering an unsafe state. When it is determined that the safety state of the system's overall inertia is a relatively safe state, it indicates that the inertia level of the power system can meet the power system frequency stability requirements under N-2 faults. When it is determined that the safety state of the system's overall inertia is an absolutely safe state, it indicates that the inertia level of the power system is relatively sufficient.

[0127] Optionally, multiple system inertia safety boundary values ​​E can be obtained. sc Quantified into multiple inertia safety factors I sc ,like Figure 4 As shown, for example, the first safety boundary value E sc1 , the second safety boundary value E sc2 and the third safety boundary value E sc3They are quantified as 0%, 100% and 200% respectively to indicate the safety level of the overall inertia of the system. The larger the inertia safety factor, the safer the inertia level of the corresponding power system.

[0128] The power system inertia safety assessment method provided in the embodiment of the present application can accurately determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node in the power system at the same time, and then, based on the overall system inertia and multiple system inertia safety boundary values, perform a safety assessment on the overall system inertia to determine the safety state of the overall system inertia, wherein multiple system inertia safety boundary values ​​are determined based on multiple levels of fault data in a preset fault set, and the obtained multiple system inertia safety boundary values ​​are used to perform an accurate safety assessment on the overall system inertia. The embodiment of the present application can accurately determine the overall system inertia and multiple system inertia safety boundary values, thereby achieving an accurate safety assessment of the overall system inertia, and obtaining the safety state of the overall system inertia, so that relevant personnel can formulate preventive measures according to the safety state.

[0129] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0130] Figure 5 Schematic diagram of the structure of the power system inertia safety assessment device provided by an embodiment of the present application. Figure 5 As shown, the power system inertia safety assessment device provided in this embodiment may include: a first acquisition module 501, a first determination module 502, a second acquisition module 503 and a second determination module 504.

[0131] The first acquisition module 501 is used to acquire voltage data, current data and frequency of each node in the power system at the same time; wherein the node corresponds to a generator or load device in the power system.

[0132] The first determination module 502 is used to determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node.

[0133] The second acquisition module 503 is used to acquire multiple system inertia safety boundary values; the multiple system inertia safety boundary values ​​are determined according to multiple levels of fault data in a preset fault set, and the preset fault set is determined according to the power system.

[0134] The second determination module 504 is configured to determine a safety state of the system overall inertia according to the system overall inertia and the plurality of system inertia safety boundary values.

[0135] Optionally, the fault data includes the maximum disturbance power, the fault loss, the maximum frequency change rate limit and the frequency shortage limit allowed by the system; each level of fault data corresponds to each system inertia safety boundary value one by one; the second acquisition module 503 is also used for:

[0136] For each level, the first minimum inertia requirement corresponding to the level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit of the level; the second minimum inertia requirement corresponding to the level is determined according to the maximum disturbance power, fault loss and frequency shortage limit allowed by the system; based on the maximum value of the first minimum inertia requirement and the second minimum inertia requirement, the system inertia safety boundary value corresponding to the level is determined.

[0137] Optionally, the preset fault set includes a DC blocking fault set and a power tripping fault set; the second acquisition module 503 is further used for:

[0138] For each level, determine whether the maximum disturbance power of the level in the DC blocking fault set is greater than or equal to the maximum disturbance power of the level in the power tripping fault set;

[0139] If the maximum disturbance power of this level in the DC blocking fault set is greater than or equal to the maximum disturbance power of this level in the power tripping fault set, then the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the DC blocking fault set;

[0140] If the maximum disturbance power of this level in the DC locking type fault set is less than the maximum disturbance power of this level in the power tripping type fault set, the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the power tripping type fault set.

[0141] Optionally, the node includes a generator node, and the generator node corresponds to a generator in the power system; the voltage data includes a voltage amplitude and a voltage phase angle, and the current data includes a current amplitude and a current phase angle; the first determination module 502 is specifically used to:

[0142] Determine the active power of each node according to the voltage amplitude, voltage phase angle, current amplitude and current phase angle of each node;

[0143] Determining a frequency change rate of each node according to the frequency of each node;

[0144] Based on the active power and frequency change rate of each node, the overall system inertia time constant of the power system is obtained;

[0145] The overall inertia of the system is obtained according to the sum of the overall inertia time constant of the system and the capacity of the generator of each generator node.

[0146] Optionally, the multiple levels include a first level, a second level, and a third level with increasing fault severity; the multiple system inertia safety boundary values ​​include a first safety boundary value, a second safety boundary value, and a third safety boundary value with increasing values; the safety state includes an unsafe state, a critical safety state, a relatively safe state, and an absolutely safe state with increasing safety levels; the second determination module 504 is specifically used to:

[0147] If the overall inertia of the system is less than or equal to the first safety boundary value, determining that the safety state of the overall inertia of the system is an unsafe state;

[0148] If the overall inertia of the system is greater than the first safety boundary value and less than or equal to the second safety boundary value, determining that the safety state of the overall inertia of the system is a critical safety state;

[0149] If the overall inertia of the system is greater than the second safety boundary value and less than or equal to the third safety boundary value, determining that the safety state of the overall inertia of the system is a relatively safe state;

[0150] If the overall inertia of the system is greater than the third safety boundary value, it is determined that the safety state of the overall inertia of the system is an absolute safety state.

[0151] Optionally, the node includes a generator node, and the generator node corresponds to a generator in the power system; the second acquisition module 503 is specifically used for:

[0152] For each level, according to the maximum disturbance power, fault loss, maximum frequency change rate limit and the first formula

[0153] Determine the first minimum inertia requirement corresponding to the level;

[0154] In the formula, is the first minimum inertia requirement, ΔP max is the maximum disturbance power, R oCoF,limit is the maximum frequency change rate limit, H ls is the failure loss, S i is the capacity of the generator of the i-th generator node, and n is determined according to the number of generator nodes.

[0155] Optionally, the second acquisition module 503 is specifically used to: according to the maximum disturbance power of the level, the fault loss amount, the frequency shortage limit allowed by the system and the second formula

[0156] Determine the second minimum inertia requirement corresponding to the level;

[0157] In the formula, is the second minimum inertia requirement, f N is the rated frequency of the power system, D is the damping coefficient of the power system, f limit is the frequency limit allowed by the power system, f limit =Δf limit -f N , Δf limit is the frequency deficiency limit allowed by the power system, f db is the dead zone frequency, R SYS It is the primary frequency regulation response rate of the power system.

[0158] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0159] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0160] Those of ordinary skill in the art will appreciate that the templates, units, and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0161] If the module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium.

[0162] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for evaluating the inertia safety of a power system, characterized in that: include: Obtain voltage data, current data and frequency of each node in the power system at the same time; where the node corresponds to a generator or load device in the power system; Determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node; Acquire multiple system inertia safety boundary values; the multiple system inertia safety boundary values ​​are determined according to multiple levels of fault data in a preset fault set, and the preset fault set is determined according to the power system; A safe state of the system overall inertia is determined according to the system overall inertia and the plurality of system inertia safety boundary values.

2. The power system inertia safety assessment method according to claim 1, characterized in that: Fault data include maximum disturbance power, fault loss, maximum frequency change rate limit and system allowable frequency shortage limit; each level of fault data corresponds to each system inertia safety boundary value; The method further comprises: For each level, determine the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss and maximum frequency change rate limit of the level; Determine the second minimum inertia requirement corresponding to the level according to the maximum disturbance power of the level, the fault loss amount and the frequency deficiency limit allowed by the system; A system inertia safety boundary value corresponding to the level is determined based on a maximum value between the first minimum inertia requirement and the second minimum inertia requirement.

3. The power system inertia safety assessment method according to claim 2, characterized in that: The preset fault set includes a DC blocking fault set and a power supply tripping fault set; For each level, determining the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level includes: For each level, determine whether the maximum disturbance power of the level in the DC blocking fault set is greater than or equal to the maximum disturbance power of the level in the power tripping fault set; If the maximum disturbance power of this level in the DC blocking fault set is greater than or equal to the maximum disturbance power of this level in the power tripping fault set, then the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the DC blocking fault set; If the maximum disturbance power of this level in the DC locking type fault set is less than the maximum disturbance power of this level in the power tripping type fault set, the first minimum inertia requirement corresponding to this level is determined according to the maximum disturbance power, fault loss and maximum frequency change rate limit in the power tripping type fault set.

4. The power system inertia safety assessment method according to any one of claims 1 to 3, characterized in that: The node includes a generator node, and the generator node corresponds to a generator in the power system; the voltage data includes a voltage amplitude and a voltage phase angle, and the current data includes a current amplitude and a current phase angle; The determining the overall system inertia of the power system based on the voltage data, current data and frequency of each node includes: Determine the active power of each node according to the voltage amplitude, voltage phase angle, current amplitude and current phase angle of each node; Determining a frequency change rate of each node according to the frequency of each node; Based on the active power and frequency change rate of each node, the overall system inertia time constant of the power system is obtained; The overall inertia of the system is obtained according to the sum of the overall inertia time constant of the system and the capacity of the generator of each generator node.

5. The power system inertia safety assessment method according to any one of claims 1 to 3, characterized in that: The multiple levels include a first level, a second level, and a third level with increasing fault severity; the multiple system inertia safety boundary values ​​include a first safety boundary value, a second safety boundary value, and a third safety boundary value with increasing values; the safety state includes an unsafe state, a critical safety state, a relatively safe state, and an absolutely safe state with increasing safety levels; Determining the safety state of the overall inertia of the system according to the overall inertia of the system and the plurality of system inertia safety boundary values ​​includes: If the overall inertia of the system is less than or equal to the first safety boundary value, determining that the safety state of the overall inertia of the system is an unsafe state; If the overall inertia of the system is greater than the first safety boundary value and less than or equal to the second safety boundary value, determining that the safety state of the overall inertia of the system is a critical safety state; If the overall inertia of the system is greater than the second safety boundary value and less than or equal to the third safety boundary value, determining that the safety state of the overall inertia of the system is a relatively safe state; If the overall inertia of the system is greater than the third safety boundary value, it is determined that the safety state of the overall inertia of the system is an absolute safety state.

6. The power system inertia safety assessment method according to claim 2, characterized in that: The nodes include generator nodes, the generator nodes corresponding to generators in the power system; For each level, determining the first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level includes: For each level, according to the maximum disturbance power, fault loss, maximum frequency change rate limit and the first formula Determine the first minimum inertia requirement corresponding to the level; In the formula, is the first minimum inertia requirement, ΔP max is the maximum disturbance power, R oCoF,limit is the maximum frequency change rate limit, H ls is the failure loss, S i is the capacity of the generator of the i-th generator node, and n is determined according to the number of generator nodes.

7. The power system inertia safety assessment method according to claim 6, characterized in that: For each level, determining the second minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and frequency deficiency limit allowed by the system of the level includes: According to the maximum disturbance power of this level, the amount of fault loss, the frequency deficiency limit allowed by the system and the second formula Determine the second minimum inertia requirement corresponding to the level; In the formula, is the second minimum inertia requirement, f N is the rated frequency of the power system, D is the damping coefficient of the power system, f limit is the frequency limit allowed by the power system, f limit =Δf limit -f N , Δf limit is the frequency deficiency limit allowed by the power system, f db is the dead zone frequency, R SYS It is the primary frequency regulation response rate of the power system.

8. The power system inertia safety assessment method according to claim 7, characterized in that: The expression of the system inertia safety boundary value is: In the formula, E sc is the safety boundary value of system inertia.

9. A power system inertia safety assessment device, characterized in that: include: The first acquisition module is used to acquire voltage data, current data and frequency of each node in the power system at the same time; wherein the node corresponds to a generator or load device in the power system; A first determination module, configured to determine the overall system inertia of the power system based on the voltage data, current data and frequency of each node; A second acquisition module is used to acquire a plurality of system inertia safety boundary values; the plurality of system inertia safety boundary values ​​are determined according to fault data of a plurality of levels in a preset fault set, and the preset fault set is determined according to the power system; The second determination module is used to determine the safety state of the overall inertia of the system according to the overall inertia of the system and the multiple system inertia safety boundary values.

10. The power system inertia safety assessment device according to claim 9, characterized in that: Fault data include maximum disturbance power, fault loss, maximum frequency change rate limit and system allowable frequency shortage limit; each level of fault data corresponds to each system inertia safety boundary value; The second acquisition module is also used to determine, for each level, a first minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and maximum frequency change rate limit of the level; determine a second minimum inertia requirement corresponding to the level according to the maximum disturbance power, fault loss amount and frequency shortage limit allowed by the system; and determine the system inertia safety boundary value corresponding to the level based on the maximum value of the first minimum inertia requirement and the second minimum inertia requirement.

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