An intelligent substation secondary protection arrangement checking method based on digital twinning

Abstract

The application relates to an intelligent substation secondary protection arrangement checking method based on digital twinning. Starting from the digital twinning power grid of an actual working condition, other devices connected with the outlet signal of the maintenance device are automatically found out, and checking on the related other devices is automatically completed, and the checking is intuitively displayed on a visual interface of the digital twinning power grid. Through a full-mode simulation method, all outlet signals of the protection device needing maintenance are found out, all protection devices receiving the signals are found out, the inlet signals of the protection devices are collected into a set, any combination signal of the set elements is sent in the digital twinning power grid, and whether a deadlock appears in the visual interface is checked.

Description

Technical Field

[0001] This invention belongs to the field of power operation and maintenance technology, specifically relating to a method for verifying secondary safety measures in intelligent substations based on digital twins. Background Technology

[0002] In smart substations, analog sampling AC circuits use Sampled Value (SV) message communication, while protection tripping, input / output information, and other information use General Object-Oriented Substation Event (GOOSE) message communication. The correspondence between virtual terminals replaces the traditional cable connections between secondary equipment, and the opening and closing of connections between secondary equipment is achieved by changing the switching state of the soft pressure plate. Therefore, secondary safety measure operations (referred to as safety operation) are transformed into a combination of operations for inspecting hard and soft pressure plates. This process is characterized by a large number of pressure plates, implicit and unintuitive operation, and the lack of a "clear electrical disconnection point," making it not intuitive.

[0003] Safety measure operation verification in smart substations mainly includes safety measure isolation verification and safety measure ticket execution verification. Safety measure isolation verification ensures effective isolation between operating and maintenance equipment. Failure to guarantee effective isolation between these two types of equipment will threaten the personal safety of maintenance personnel. Safety measure ticket execution verification involves verifying each step of the safety measure operation in the safety measure ticket during execution. The goal of this verification is to ensure the safety of each step and to promptly identify potential protection malfunctions such as false locking or activation. Many power outages are caused by improper operation during safety measure procedures, leading to false activation or locking, resulting in significant economic losses.

[0004] Power technology professionals have proposed numerous verification techniques for secondary safety measures in smart substations. These include implementing highly intelligent applications such as anti-misoperation interlocking, intelligent safety ticketing, and intelligent alarms based on a fully configured Substation Configuration Description (SCD) file model; and from the perspective of preventing errors in secondary safety measures in smart substations, proposing an automatic verification technology for safety ticketing based on the principle of safety measure isolation to reduce the burden on secondary equipment operators and minimize errors. Other researchers, focusing on the application of soft pressure plates in smart substations, have proposed basic principles and specific strategies for preventing misoperation using soft pressure plates. This involves formalizing the anti-misoperation logic of soft pressure plates in the form of logical expressions, providing an automatic generation method, and an implementation scheme in the monitoring backend. However, when applied to full-station modeling, the complexity of these expressions increases exponentially, making them difficult to apply to the actual verification of secondary safety measures in smart substations.

[0005] The existing secondary protection checking technology of the intelligent substation is started from the protection logic, the soft pressure plate anti-misoperation logic is formalized in the form of a logic expression, and a connection matrix is generated, when checking the secondary protection, each operation in the set of protection operation steps is checked for matrix connectivity, and the connection matrix is modified according to the operation. Obviously, when applied to full station modeling, the complexity of the expression increases in a geometric progression, thereby bringing a huge workload; on the other hand, due to the characteristics of no "obvious electrical disconnect point", etc., it is not intuitive and difficult to intuitively show the effect of the checking on the operation condition diagram.

[0006] In view of the fact that there is still a lack of effective secondary protection checking means for the current intelligent substation, it is difficult to ensure that the maintenance operations will not adversely affect the power system, and an effective secondary protection checking method for the intelligent substation must be proposed. Under the background that the State Grid Corporation of China has realized the integration of dispatching and control, Beijing Kedong Company develops a digital twin power grid system for the integration of dispatching and control on the basis of the intelligent dispatching platform, which combines the dispatching simulation, device simulation and signal simulation into an integrated full-range, full-process and full-scene device monitoring visual simulation training system, and can select typical signals in the intelligent substation to establish a signal simulation model from the aspects of signal analysis, signal cause, hidden danger analysis and disposal measures; the state of the field device, the action process of the protection and measurement and control device, the signal secondary circuit and the signal uploading link are simulated and trained. When the digital twin power grid starts simulation from the operation data section of a certain dispatching area in real time, the digital twin power grid of the dispatching area can also be constructed. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art and provide a secondary protection checking method for an intelligent substation based on digital twinning,

[0008] To achieve the above-mentioned purpose, the technical solution of the present application is as follows: a secondary protection checking method for an intelligent substation based on digital twinning, comprising the following steps:

[0009] Step 1, obtaining all outlet signals of the protection device to be maintained from the operation ticket;

[0010] Step 2, obtaining all protection devices to be checked according to all outlet signals;

[0011] Step 3, collecting the inlet signals of all protection devices to be checked into a checking signal set and determining the test value, the checking signal set containing N signals;

[0012] Step 4, checking all protection devices to be checked based on the digital twin power grid of the region using the checking signal set, if the check is blocked, the checking of the secondary safety measure operation fails, the corresponding operation ticket is problematic, and the whole checking process is exited; otherwise, the checking is successful.

[0013] Compared with the prior art, the present application has the following beneficial effects: starting from the digital twin power grid of the actual working condition, the present application automatically finds other devices connected with the outlet signal of the maintenance device, and automatically completes the checking of these related other devices, while intuitively displaying on the visual interface of the digital twin power grid. This intelligent substation secondary protection arrangement checking method based on digital twinning has the following advantages:

[0014] 1. Only the other devices connected with the outlet signal of the maintenance device in the digital twin power grid at the checking time are concerned, reducing the complexity of establishing the full-station anti-misoperation logic expression;

[0015] 2. The measurement values of the two protection device input electrical quantities associated with the maintenance device are selected according to the switch quantity state and the setting value;

[0016] 3. The measurement values of the protection device input electrical quantities less than the setting value are calculated by using the digital twin power grid;

[0017] 4. The combination mode is adopted to automatically simulate the subsequent working condition signals from the digital twin power grid at the checking time, achieving full working condition checking of the maintenance device;

[0018] Therefore, the present application finds all the protection devices receiving the outlet signal of the protection device to be maintained by the full-mode simulation method, collects the inlet signals of these protection devices into a set, sends any combination signal of the set elements in the digital twin power grid, and checks whether a deadlock will occur in the visual interface. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a data connection relationship diagram between secondary devices;

[0020] Figure 2 is a GOOSE / SV subscription relationship between secondary devices;

[0021] Figure 3 is a trip logic diagram of line protection device PCS-931;

[0022] Figure 4 is a remote trip protection logic diagram of line protection device PCS-931. DETAILED DESCRIPTION

[0023] The technical solutions of the present application will be specifically described below in combination with the drawings.

[0024] The present application provides an intelligent substation secondary protection arrangement checking method based on digital twinning, including the following steps:

[0025] Step 1, obtaining all outlet signals of the protection device to be repaired from the operation ticket;

[0026] Step 2, obtaining all protection devices to be checked according to all outlet signals;

[0027] Step 3, collecting the inlet signals of all protection devices to be checked into a checking signal set and determining a test value, the checking signal set containing N signals;

[0028] Step 4, based on the digital twin power grid of the region, checking all protection devices to be checked using the checking signal set, if the check is blocked, the checking of the secondary safety measure operation fails, the operation ticket is problematic, and the entire checking process is exited; otherwise, the checking is successful.

[0029] Further, in step 2, the method for obtaining all protection devices to be checked according to all outlet signals comprises:

[0030] Obtaining the connection relationship between the station secondary equipment data;

[0031] Obtaining the set of secondary protection devices to be checked according to the connection relationship between the station secondary equipment data.

[0032] Further, the connection relationship between the station secondary equipment data comprises GOOSE / SV receiving subscription relationship, device output and input soft press plate opening relationship, and physical connection relationship;

[0033] Obtaining the connection relationship between the station secondary equipment data comprises obtaining SCD file, ICD file and SPCD file.

[0034] Further, the method for obtaining the set of secondary protection devices to be checked according to the connection relationship between the station secondary equipment data comprises:

[0035] Through the SCD file, the SPCD file, the ICD file and the device instruction manual, the logical connection (i.e. virtual loop) and the physical connection (i.e. optical cable) relationship between the devices can be obtained;

[0036] When the operation ticket is issued to be checked, the secondary protection devices involved in each step in the ticket can be added to the set of secondary protection devices to be checked;

[0037] The elements of the set of secondary protection devices to be checked are checked in turn, the issuing signal is obtained from the rightmost side of the protection logic, and is added to the set of secondary protection issuing signals to be checked.

[0038] Further, through the SCD file, the SPCD file, the ICD file and the device instruction manual, the logical connection (i.e. virtual loop) and the physical connection (i.e. optical cable) relationship between the devices can be obtained, including:

[0039] (1)According to the attributes of iedName, ldInst, lnClass and doName under the ExtRef label under the element IED in the SCD file, the path of the output virtual terminal can be parsed; and according to the intAddr attribute under the ExRef label, the path of the input virtual terminal of the IED can be parsed, so that the secondary virtual circuit connection relationship can be constructed, and thus the topological structure modeling of all secondary virtual circuits in the smart substation can be realized.

[0040] (2) Through the device manual of each ICD file and the IED of the type, a mapping relationship library of the soft panel configuration path of each type of IED and the secondary virtual circuit is established.

[0041] (3) The mapping relationship between the logical circuit and the physical circuit can be obtained by searching the logical virtual circuit in the SCD file and searching the physical connection circuit in the SPCD file.

[0042] Further, the entry signals of the protection devices of all the signals of the protection devices to be checked are collected into a checking signal set, including:

[0043] The GOOSE / SV communication association is performed on each element of the secondary protection device set to be checked in turn, and the other protection devices subscribing to the SV messages sent by each protection element are added to the associated secondary protection device set;

[0044] The information of the device is obtained from the leftmost input of the protection logic of each protection element of the associated secondary checking protection device set, and the information is added to the checking signal set.

[0045] The value of the element in the checking signal set can be divided into two categories: one is the switch quantity type, such as the above-mentioned “A-phase has flow”, “select A-phase”, “B-phase has flow”, “select B-phase”, “C-phase has flow” and “select C-phase”, and the test value is selected as 0 or 1, indicating two states of having and not having; the other is the electrical quantity type, which needs to be converted into the switch quantity type of 0 or 1.

[0046] Further, the method for determining the test includes constructing a digital twin power grid, and the electrical quantity test value is selected by power grid calculation, including:

[0047] The data of the regional power grid is obtained from the database of the national power grid to construct the digital twin power grid, including the network topology and parameter static data, and the section data of the local power grid running at the billing moment;

[0048] The model of the digital twin power grid contains all primary power equipment of the region, and also contains various secondary relay protection device models in the substation of the region, which are the same type as the secondary protection devices in the corresponding substation in the actual physical power grid; in addition, there are CT / PT secondary side currents, voltages and other electrical quantities.

[0049] The digital twin power grid adopts a steady-state power flow calculation model. For a network with n nodes with 4n independent electrical parameters (Pi, Qi, Ui, θi, i = 1, 2, …, n), the power flow calculation first calculates the admittance matrix Y according to the topological structure and parameters of the power grid; then the nodes are pre-divided into PV and PQ nodes according to their properties, where the PV node is a voltage node, at this time P and U are known, and Q is a to-be-solved quantity (assuming m); and the PQ node is a load node, at this time P and Q are known, and U and θ are unknown quantities (assuming l). The elements of the admittance matrix Y are represented by the polar coordinates of conductance and susceptance, that is, Y ij = G ij +jB ij , where G is the conductance, indicating the strength of the current transmission capability of a certain conductor; and B is the susceptance, defined as the inverse of the reactance.

[0050] The n system state variables are solved by the Newton-Raphson method, and for the PQ node, there are the following l groups of equations:

[0051]

[0052] where (i = 1, 2, …, l). For the PV node, there are the following m groups of equations:

[0053]

[0054] Based on formulas (1) and (2), the corresponding Jacobian matrix is generated as shown in formula (3):

[0055]

[0056] where δ ij is 1 when i is equal to j, and 0 when i is not equal to j. The node active power P and reactive power Q are solved by the Newton-Raphson method as shown in formula (4).

[0057]

[0058] The digital twin power grid starts running with the section data of the local power grid at the time of billing as the initial value, enters the simulation calculation in a loop, and approaches the setting value by a percentage of the measured value at each calculation. For example, in order to obtain the measured value of the "AB phase current variation", assuming that the setting value is 10 amperes, the current of phases A and B are 50 amperes respectively, then phase A is increased by 1%, phase B is decreased by 1%, and the change values of P and Q on the bus caused by this are calculated, and the new power flow on the bus is calculated by substituting the formula 4, which is used as the section data, and the above process is repeated.

[0059] If the AB phase current variation is greater than 10 amperes, then a set of A phase and B phase measured values that satisfy the conversion of the measured value of the "AB phase current variation" into the switching value 1 is found. If not found, then the twin data power grid starts running with the section data of the local power grid at the time of billing as the initial value, enters the simulation calculation in a loop, at this time phase A is decreased by 1%, phase B is increased by 1%, and the above steps are repeated.

[0060] Further, the method for checking all protection devices to be checked by using the check signal set comprises:

[0061] calculating the number N of the check signal set;

[0062] taking , one by one, from the N signals in the set, , one by one, from the N signals in the set, , one by one, from the N signals in the set, and so on, , one by one, from the N signals in the set, to send, and to test whether a deadlock will occur in the digital twin power grid.

[0063] If a deadlock is found, the secondary safety measure operation fails, the operation ticket is problematic, and the whole checking process is exited; otherwise, the checking is successful.

[0064] taking , one by one, from the N signals in the set, , one by one, from the N signals in the set, , one by one, from the N signals in the set, and so on, , one by one, from the N signals in the set, to send, and to test whether a deadlock will occur in the digital twin power grid.

[0065] Step A, the section data of the local power grid at the time of billing is the initial value, and the combination number i is 1;

[0066] Step B, taking from the check signal set to generate a new set P, the number of which is j, and each element in P is a subset containing i signals;

[0067] Step C, testing the j subsets of the new set P:

[0068] Step D: Take a subset m and start the digital twin grid with the "local grid operation section data at the time of invoicing" as the initial value. Assign the signal values ​​in m to the digital twin grid in one go within the simulation step size, and check whether blocking occurs through the visualization interface.

[0069] Step E: If an interlock is detected, the verification of the secondary safety measure operation fails, this operation ticket is problematic, and the entire verification process is exited; otherwise, loop C is performed until the jth time.

[0070] Step F: Increase the value of i. If it is less than N / 2, repeat step B. Otherwise, the verification of the secondary safety measure operation is successful, and there is no problem with this operation ticket.

[0071] The following are specific implementation examples of the present invention.

[0072] Example 1:

[0073] The technical solution in this embodiment involves identifying all protection devices receiving the output signals of the protection device requiring maintenance, collecting the input signals of these protection devices into a set, and then checking if this set contains N signals. Then, these N signals are sequentially selected... indivual, indivual, indivual,..., To detect deadlocks in the digital twin power grid, data transmission needs to be initiated. This requires establishing data connectivity between secondary devices in the smart substation during the initial implementation phase.

[0074] 1. Establish a set of signals affected by the maintenance equipment.

[0075] 1.1 Establish data connectivity between secondary equipment within the station.

[0076] Based on the Smart Substation SCD file, IED Capability Description (ICD) file, device manual, and DL...

[0077] The Physical Fiber Circuit Description (SPCD) file of / T1777—2017 "Technical Specification for Fiber Optic Circuits in Secondary Equipment Cabinets of Intelligent Substations" establishes a static topology model for safety measure verification. The SPCD file mainly specifies the technical requirements for the description files, circuit codes, and identification information of fiber optic circuits and twisted-pair circuits in the secondary circuits of intelligent substations, as well as the description files.

[0078] The data connectivity between secondary devices can be achieved by Figure 1 Let a in the figure represent ij This indicates the data transmission status from device i to device j; a ji This indicates the data transmission status from device j to device i.

[0079] The connectivity between the two devices established by the above two channels is determined by the following three relationships:

[0080] (1) GOOSE / SV subscription relationship

[0081] Communication in smart substations uses GOOSE / SV messages.

[0082] GOOSE: Generic Object-Oriented Substation Event, is a type of substation event oriented towards generic objects. It is primarily used to enable information transmission between multiple intelligent electronic devices (IEDs), including transmitting various signals (commands) such as tripping / closing and interlocking, and has a high probability of successful transmission.

[0083] SV (Sampled Value) is a model object and service that exchanges sampled values ​​in a sampled dataset based on a publish / subscribe mechanism, as well as the mapping of these model objects and services to ISO / IEC 8802-3 frames.

[0084] If device j does not subscribe to GOOSE / SV messages from device i, then a is considered to be... ij The value must be 0. The above GOOSE / SV subscription relationship constitutes the secondary virtual loop system of the smart substation. Its topology is given by the SCD file, such as... Figure 2 As shown:

[0085] (2) Relationship between the output and input soft pressure plates of the equipment

[0086] A soft pressure plate is set in the secondary virtual loop, providing a software-implemented communication channel switch based on GOOSE / SV message communication. Therefore, if a is controlled... ij The soft pressure plate corresponding to the virtual circuit is not engaged, and it is still considered that a ij =0. The soft pressure plate settings of the device and the ports of its secondary virtual circuits are described in the SCD file, but the correspondence between them cannot be obtained from the SCD file. It can be obtained by combining the device's ICD file with the device manual provided by the manufacturer.

[0087] (3) Physical connection relationship

[0088] The secondary virtual loop configuration provided in the SCD file is logical. In a smart substation, connectivity between secondary devices requires a physical fiber optic connection; that is, the existence of the secondary virtual loop depends on the existence of the fiber optic connection channel. Therefore, if no physical connection exists (or if a connection exists but a fault occurs), then a... ij =0.

[0089] 1.2 Establish a collection of secondary protection devices that need to be verified.

[0090] The three relationships for determining the connected state correspond to three static description files of the smart substation, namely, the SCD file, the ICD file and the SPCD file. By using the three files, the connected state between the secondary devices in the smart substation can be modeled in the static topology in the following three steps:

[0091] (1) The path of the output virtual terminal can be parsed according to the attributes of iedName, ldInst, lnClass and doName under the ExtRef label of the element IED in the SCD file. The path of the input virtual terminal of the IED can be parsed according to the intAddr attribute under the ExRef label, and then the connection relationship of the secondary virtual circuit can be constructed, thereby the topology structure modeling of all the secondary virtual circuits in the smart substation can be realized.

[0092] (2) Since the SCD file is the instantiation application of the ICD file, the corresponding relationship between the soft panel configuration path of the specified IED and the secondary virtual circuit in the SCD file is the same as that of the ICD file of the IED. The corresponding relationship between the soft panel configuration path and the secondary virtual circuit in the ICD file is defined in the device specification of the IED. Therefore, the mapping relationship library of the soft panel configuration path and the secondary virtual circuit of each type of IED can be established through each ICD file and the device specification of the IED.

[0093] (3) The physical fiber link configuration of each IED is described in the Communication label in the SCD file, including the port number and the cable name. By indexing the port number and the cable name in the SPCD file, the specific physical connection circuit information of the smart substation can be obtained. Therefore, by searching the logical virtual circuit in the SCD file and searching the physical connection circuit in the SPCD file, the mapping relationship between the logical circuit and the physical circuit can be obtained.

[0094] Therefore, by using the SCD file, the SPCD file, the ICD file and the device specification, the logical connection (i.e. the virtual circuit) and the physical connection (i.e. the cable) relationship between the devices can be obtained, as shown in the above Figure 2 When the operation ticket is issued for checking, the secondary protection devices involved in each step of the ticket can be added to the set of secondary protection devices to be checked. The elements of the set of secondary protection devices to be checked are checked in turn, the issuing signal is obtained from the rightmost side of the protection logic, and the secondary protection issuing signal set to be checked is added, such as the "trip A-phase outlet", "trip B-phase outlet", "trip C-phase outlet" and the like. Figure 3

[0095] 1.3, Establishing a checking signal set and its test value

[0096] ​The GOOSE / SV communication associations are sequentially established for each element of the secondary protection device set to be verified. Other protection devices that subscribe to the SV messages issued by each protection element are added to the associated secondary protection device set. Clearly, for each protection element in the associated secondary protection device set, at least one of its leftmost input signals belongs to the set of output signals of the secondary protection to be verified. After setting these input signals belonging to the set of output signals of the secondary protection to be verified to the maintenance state (the maintenance pressure plate on the protection device is pressed), it is necessary to verify whether the protection device will lock out. Although some protection devices' protection logic considers the situation where the input signal is in the maintenance state, in actual engineering projects, protection devices from multiple manufacturers and of multiple models are often used, and it cannot be guaranteed that lockout problems will not occur.

[0097] Therefore, for each protection element in the associated secondary verification protection device set, the information of the device is obtained by starting from the leftmost input of its protection logic, as shown above. Figure 3 The information such as "longitudinal differential protection", "change distance", "distance I and II segments", "zero sequence II segment", "current in phase A", "select phase A", "current in phase B", "select phase B", "current in phase C", and "select phase C" is added to the verification signal set.

[0098] The values ​​of elements in the verification signal set can be divided into two categories. One category is switch quantities, such as the signals "current in phase A", "select phase A", "current in phase B", "select phase B", "current in phase C", and "select phase C" mentioned above. Their test values ​​are 0 or 1, representing the presence or absence of current. The other category is electrical quantities, which need to be converted into 0 or 1 switch quantities, such as... Figure 4 The diagram shows "A / B phase current change", "C phase current change", and "CA phase current change". To achieve this, the setting value of the electrical quantity for the protected device is first obtained. Then, a test quantity greater than this setting value is selected, and its logic is set to 1. Next, a test quantity less than this setting value is selected, and its logic is set to 0. Since the selection of electrical quantity test values ​​may cause the power grid calculation to be in a non-convergent state, meaning it could lead to a power system collapse, it is clear that the electrical quantity test values ​​need to be selected through power grid calculation. This necessitates the construction of a digital twin power grid.

[0099] 1.4 Select electrical measurement values ​​based on the digital twin power grid

[0100] The data of the local power grid can be obtained from the database of the national power grid to construct the digital twin power grid, including static data such as network topology and parameters, and section data of the local power grid at the billing time (the data can be used to calculate the electrical measurement value greater than the setting value, so that the electrical measurement value is converted to the 0 value of the switch quantity; the electrical measurement value less than the setting value needs to be calculated below, so that it is converted to the 1 value of the switch quantity). The model of the digital twin power grid includes all the primary power equipment of the region, such as line class, transformer class, generator class, switch class and load models. At the same time, it also includes various secondary relay protection device models in the substation in the region, that is, the real devices such as line protection, main transformer protection, bus protection, capacitor protection, reactor protection and station transformer protection, which are the same type as the secondary protection devices in the corresponding substation in the actual physical power grid; in addition, there are CT / PT secondary side current, voltage and other electrical quantities.

[0101] The steady-state power flow calculation model of the digital twin power grid has 4n independent electrical parameters (Pi, Qi, Ui, θi, i = 1, 2, …, n) for an n-node network. The power flow calculation first calculates the admittance matrix Y according to the topology and parameters of the power grid; then the nodes are pre-divided into PV and PQ nodes according to their properties, where the PV node is the voltage node, and P and U are known, and Q is the to-be-solved quantity (assuming m); and the PQ node is the load node, and P and Q are known, and U and θ are unknown quantities (assuming l). The elements of the admittance matrix Y are represented by the polar coordinates of conductance and susceptance, that is, Y ij = G ij +jB ij , where G is the conductance, indicating the strength of the current transmission capability of a certain conductor; and B is the susceptance, defined as the inverse of the reactance.

[0102] The n system state variables are solved by the Newton-Raphson method. For the PQ node, there are the following l groups of equations:

[0103]

[0104] where (i = 1, 2, …, l). For the PV node, there are the following m groups of equations:

[0105]

[0106] where (i = 1, 2, …, m). Based on formulas (1) and (2), the corresponding Jacobian matrix is generated as shown in formula (3):

[0107]

[0108] where δ ijThe value is 1 when i equals j and 0 when i does not equal j. The active power P and reactive power Q of the node are solved using the Newton-Raphson method, as shown in formula (4).

[0109]

[0110] The twin data grid starts operating with the local grid's cross-sectional data at the time of invoicing as the initial value, entering a cyclical simulation calculation. In each calculation, it approximates the set value by a percentage of the measured value. For example, to obtain the measured value of "change in current between phases A and B", assuming the set value is 10 amps and the current of phases A and B in the current operating section is 50 amps each, phase A is increased by 1% and phase B is decreased by 1%. At the same time, the resulting changes in P and Q on the line bus are calculated, and the new power flow on the bus is calculated by substituting into Formula 4. This is used as the cross-sectional data, and the above process is repeated.

[0111] If the change in current between phases A and B is greater than 10 amperes, then a set of measurements that satisfies the requirement of converting the "change in current between phases A and B" into the measurement values ​​of phase A and phase B of switch quantity 1 has been found. If no such set is found, the twin data grid will start running again with the cross-sectional data of the local power grid at the time of invoicing as the initial value, and enter the cyclic simulation calculation. At this time, phase A will decrease by 1% and phase B will increase by 1%, and the above steps will be repeated.

[0112] 2. Verification of the verification signal set in the digital twin power grid

[0113] When starting the verification of secondary safety measures for smart substations, the twin data grid is started with the cross-sectional data of the local power grid at the time of invoicing as the initial value, and enters the cyclic simulation calculation.

[0114] In the simulation, the calculation parameters (including the state variables of secondary protection devices, etc.) are changed by combining the selection of the verification signal set. Assuming that the verification signal set has N signals, these N signals are selected sequentially. indivual, indivual, indivual,..., Send one to see if deadlock occurs in the digital twin power grid.

[0115] Detailed verification process:

[0116] 1. Calculate the set of secondary protection devices that need to be verified;

[0117] 2. Calculate the set of secondary protection output signals that need to be verified;

[0118] 3. Calculate the associated secondary verification protection device set;

[0119] 4. Calculate the set of verification signals;

[0120] 5. Calculate the measurement value of the set of check signals;

[0121] 6. Calculate the number N of the set of check signals;

[0122] 7. The section data of the local power grid in operation at the time of billing is the initial value, and the combination number i is 1;

[0123] 7.1 Take a subset m from the set of check signals; Generate a new set P, the number of which is j, and each element in P is a subset containing i signals;

[0124] 7.1.1 Test the j subsets of the new set P:

[0125] 7.1.2 Take a subset m, start the digital twin power grid with the initial value of the section data of the local power grid in operation at the time of billing, assign the signal values in m to the digital twin power grid at one time within the simulation step, and check whether the lockout occurs through the visual interface;

[0126] 7.1.3 If the lockout is checked, the check of the secondary safety measure operation fails, the operation ticket has a problem, and the whole check process is exited; otherwise, the cycle of 7.1.2 is performed until j times.

[0127] 8. Increase the value of i, if it is less than N / 2, repeat 7.1, otherwise the check of the secondary safety measure operation succeeds, and the operation ticket has no problem.

[0128] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program codes.

[0129] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one flow or multiple flows and / or blocks Figure 1 The functions specified in one flow or multiple flows and / or blocks

[0130] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0131] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions that are executed on the computer or other programmable apparatus provide steps for implementing the Figure 1 function specified in the flow or flows and / or blocks Figure 1 of the block or blocks.

[0132] The above description is only preferred embodiments of the present application, it should be pointed out that, for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can also be made, these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A method for verifying secondary safety measures in intelligent substations based on digital twins, characterized in that, Includes the following steps: Step 1: Obtain all output signals of the protection device to be inspected from the operation ticket; Step 2: Based on all exit signals, obtain all protection devices that need to be verified; Step 3: Collect the input signals of all protection devices that need to be checked into a check signal set and determine the test values. The check signal set contains N signals. Step 4: Based on the digital twin power grid of this region, use the verification signal set to verify all protection devices that need to be verified. If a lockout is detected, the verification of the secondary safety measure operation fails, the corresponding operation ticket is problematic, and the entire verification process is terminated. Otherwise, the verification was successful; In step 4, the construction of the digital twin power grid and the method for selecting electrical quantity test values ​​through calculations using the digital twin power grid are as follows: Data from the national power grid database is used to construct a digital twin power grid, including static data on network topology and parameters, as well as cross-sectional data of the local power grid at the time the operation ticket is issued. The model of the digital twin power grid includes all primary power equipment in the region, as well as various secondary protection equipment models in the substations of the region. These devices are the same type as the secondary protection equipment in the corresponding substations in the actual physical power grid. The digital twin power grid employs a steady-state power flow calculation model for n nodes with 4n independent electrical parameters (P). i Q i U i θ i For a network (i = 1, 2, ..., n), power flow calculation first determines the admittance matrix Y based on the network topology and parameters. Then, nodes are pre-classified into two types: PV and PQ nodes, where PV nodes are voltage nodes (P and U are known, and Q is an unknown quantity, denoted as m). PQ nodes are load nodes (P and Q are known, and U and θ are unknown quantities, denoted as l). The elements of the admittance matrix Y are represented by polar coordinates of conductance and susceptance, i.e. , where G is conductance, which represents the strength of a conductor's ability to carry current; B is susceptance, which is defined as the reciprocal of reactance; The n system state variables are solved using the Newton-Raphson method. For the PQ node, the following set of equations are obtained: （1） in, For PV nodes, there are the following m sets of equations: （2） in, ; Based on formulas (1) and (2), the corresponding Jacobian matrix is ​​generated as shown in formula (3): （3） in It represents 1 or 0, with a value of 1 when i equals j and a value of 0 when i does not equal j; The active power P and reactive power Q at the nodes are obtained by using the Newton-Raphson method, as shown in formula (4): （4） The digital twin power grid starts operating with the cross-sectional data of the power grid in the region at the time of invoicing as the initial value, and enters a cyclical simulation calculation. In each calculation, it approaches the set value by a percentage of the measured value.

2. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 1, characterized in that, In step 2, the method for obtaining all protection devices that need to be verified based on all output signals is as follows: Obtain the connectivity relationships between secondary equipment within the station; Based on the connectivity of data between secondary equipment within the station, obtain and establish a set of secondary protection equipment that needs to be verified.

3. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 2, characterized in that, The connectivity relationships between the secondary equipment within the station include GOOSE / SV receiving and subscription relationships, the output and input soft pressure plate opening and closing relationships of the equipment, and physical connection relationships. Obtain the connectivity between secondary devices within the station, including obtaining SCD files, ICD files, and SPCD files.

4. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 3, characterized in that, The method for obtaining and establishing the set of secondary protection devices to be verified based on the connectivity of data between secondary equipment within the station is as follows: By using SCD files, ICD files, SPCD files, and the instruction manuals for secondary protection devices, the relationship between logical connections (virtual loops) and physical connections (optical cables) between secondary protection devices can be obtained. When an operation ticket is issued and awaits verification, the secondary protection devices involved in each step of the operation ticket are added to the set of secondary protection devices that need to be verified. Check each element of the secondary protection device set that needs to be checked in turn, obtain the output signal from the rightmost side of its protection logic, and add it to the set of output signals of the secondary protection that needs to be checked.

5. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 4, characterized in that, The relationship between the logical connections (virtual loops) and physical connections (optical cables) between secondary protection devices can be obtained through SCD files, ICD files, SPCD files, and the instruction manuals for the secondary protection devices as follows: 1) Parse the path of the output virtual terminal according to the attributes including iedName, ldInst, lnClass and doName under the ExtRef tag under the element IED in the SCD file; then parse the path of the input virtual terminal of the element IED according to the intAddr attribute under the ExRef tag, and construct the secondary virtual circuit connection relationship, thereby realizing the topology modeling of all secondary virtual circuits in the smart substation. 2) By using the ICD files and the instruction manuals for the secondary protection devices of the corresponding IED models, establish a mapping relationship library between the soft pressure board configuration paths and secondary virtual circuits for each type of IED; 3) Obtain the mapping relationship between logical loops and physical loops by searching for logical virtual loops in the SCD file and physical connection loops in the SPCD file.

6. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 3, characterized in that, The method for collecting the input signals of all protection devices requiring verification into a verification signal set is as follows: Sequentially perform GOOSE / SV communication association for each element of the secondary protection device set that needs to be verified, and add other protection devices that subscribe to the SV messages sent by each protection element to the associated secondary protection device set; For each protection element in the associated secondary verification protection device set, obtain the device information from the leftmost input of its protection logic, and add this information to the verification signal set. The values ​​of the elements in the verification signal set are divided into two categories: one is the switch quantity category, whose test value is selected as 0 or 1, representing the two states of presence and absence; the other is the electrical quantity category, which needs to be converted into a switch quantity category of 0 or 1.

7. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 1, characterized in that, In step 4, the method for verifying all protection devices requiring verification using the verification signal set is as follows: Calculate the number N of the verification signal set; Take N signals in the set in sequence indivual, indivual, indivual,……, One is sent to check whether deadlock will occur in the twin digital twin power grid; If an interlock is detected, the verification of the secondary safety measures operation fails, the corresponding operation ticket is problematic, and the entire verification process is terminated. Otherwise, the verification will succeed.

8. The method for verifying secondary safety measures in a smart substation based on digital twins according to claim 7, characterized in that, Take N signals in the set in sequence indivual, indivual, indivual,……, The method for sending data to check whether deadlock will occur in the digital twin power grid is as follows: Step A: When the operation ticket is issued, the cross-sectional data of the power grid operation in this area are the initial values, and the number of combinations i is 1; Step B: Extract from the verification signal set Generate a new set P with j elements, where each element in P is a subset containing i signals; Step C: Test the j subsets of the new set P: Step D: Take a subset m and start the digital twin grid with the "local power grid operation section data at the time of invoicing" as the initial value. Assign the signal values ​​in m to the digital twin grid in one go within the simulation step size, and check whether blocking occurs through the visualization interface. Step E: If an interlock is detected, the verification of the secondary safety measures operation fails, the corresponding operation ticket is problematic, and the entire verification process is terminated. Otherwise, loop C continues until it has run j times; Step F: Increase the value of i. If it is less than N / 2, repeat step B. Otherwise, the verification of the secondary safety measure operation is successful, and the corresponding operation ticket is correct.

Images