Power grid equipment communication management system

Abstract

The invention belongs to the technical field of power grids, and particularly relates to a power grid equipment communication management system. A power grid is connected with a high-voltage switch cabinet, and the high-voltage switch cabinet is connected with a low-voltage switch cabinet through a transformer; the high-voltage switch cabinet is connected with the plurality of low-voltage switch cabinets through the transformer in a looped network wiring mode. The high-voltage switch cabinet is connected with a plurality of low-voltage switch cabinets through the transformer in a looped network wiring mode, over-current signals and short-circuit signals of a plurality of groups of circuits in the low-voltage switch cabinets are recorded and analyzed, automatic closing is achieved in cooperation with the automatic reclosing module, and after closing fails in a period, the communication module is used for uploading the signals to the system, so that the reliability of the system is improved. In order to solve the problem that a low-voltage line of the low-voltage switch cabinet represents a multi-time overcurrent circuit but a circuit breaker is not disconnected, circuit maintenance needs to be arranged, power supply can be quickly recovered under the condition that a small fault occurs in a power grid, and an abnormal circuit group can be quickly responded when an abnormality occurs; and a maintainer can be helped to quickly position the low-voltage circuit group needing to be maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of power grids, and particularly to a communication management system for power grid equipment. Background Art

[0002] The communication management system for power grid equipment aims to achieve real-time data acquisition, status monitoring, fault diagnosis and cooperative control of equipment such as high-voltage switch cabinets, transformers, and low-voltage switch cabinets, and improve the reliability, safety and efficiency of power grid operation.

[0003] The existing patent (CN117638928B) is a smart distribution network management system based on cloud computing; in the above patent, the prediction of power grid faults is completed. In power grid faults, how to quickly analyze the location of power grid faults can save a large amount of troubleshooting work for maintenance personnel, but the above-mentioned fault prediction and potential fault risks cannot be intuitively reflected, and the analysis of fault causes is lacking;

[0004] In the actual operation of power grid equipment, it is inevitable that tripping problems will occur. How to ensure that the low-voltage switch cabinet does not expand its impact on the high-voltage switch cabinet and quickly restore power supply is very important;

[0005] At present, the existing communication management system for power grid equipment does not achieve effective cooperative control among high-voltage switch cabinets, transformers and low-voltage switch cabinets, and cannot avoid power outages in a larger area caused by local circuit faults.

[0006] Therefore, it is necessary to provide a communication management system for power grid equipment to solve the above technical problems. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a communication management system for power grid equipment, which is used to solve the problems that power supply cannot be quickly restored when small faults occur in the power grid, abnormal circuit groups can be quickly detected when abnormalities occur, and maintenance personnel cannot be assisted in quickly locating the low-voltage circuit groups that need to be repaired.

[0008] The communication management system for power grid equipment provided by the present invention has the power grid connected to the high-voltage switch cabinet, and the high-voltage switch cabinet is connected to the low-voltage switch cabinet through a transformer;

[0009] The high-voltage switch cabinet is connected to multiple low-voltage switch cabinets through a ring network wiring method by means of a transformer;

[0010] In each group of circuits of the low-voltage switch cabinet, a protection module composed of a current transformer, an overcurrent relay, and a circuit breaker is adapted, and a signal module is set for the protection module to record the detection signal of the current transformer, the overcurrent signal of the overcurrent relay, and the disconnection signal of the circuit breaker, and upload the record to the storage unit;

[0011] In several groups of circuits of the low-voltage switchgear, binary signals are used for recording. Here, 0 represents that the circuit breaker of this group of circuits is disconnected, 100 represents multiple over-current circuits and the circuit breaker is disconnected, 1 represents that the circuit breaker of this group of circuits is not disconnected, and 11 represents multiple over-current circuits but the circuit breaker is not disconnected;

[0012] Automatic reclosing module: An automatic reclosing module is set inside the high-voltage switchgear. When the signal uploaded by the signal module of the low-voltage switchgear is "0" or "100", the automatic reclosing module is started. If the reclosing fails twice within one cycle, the automatic reclosing module is suspended;

[0013] Communication module: When the automatic reclosing module is suspended, it uploads to the system through the communication module, and the system notifies for maintenance;

[0014] Early warning module: When the low-voltage switchgear uploads a signal of "11", it uploads to the system to remind that there is a risk in the circuit with the "11" signal in this low-voltage switchgear.

[0015] Preferably, N: The number of circuit groups in the low-voltage switchgear;

[0016] T: The cycle time of automatic reclosing;

[0017] K: The counter for the number of attempts of automatic reclosing (k ∈ {0, 1, 2});

[0018] Circuit status signal: Si(t): The status signal of the i-th group of circuits at time t (Si ∈ {0, 1, 11, 100}, i = 1, 2,..., N);

[0019] A(t): The trigger flag of automatic reclosing (A ∈ {0, 1}, 0 = not triggered, 1 = triggered);

[0020] F(t): The failure flag of automatic reclosing (F ∈ {0, 1}, 0 = not failed, 1 = failed);

[0021] Trigger conditions for automatic reclosing:

[0022] When there is at least one group of circuits satisfying the following conditions, automatic reclosing is triggered;

[0023]

[0024] Otherwise: A(t) = 0.

[0025] Preferably, determination of automatic reclosing failure:

[0026] If the reclosing fails continuously twice within one cycle T, the automatic reclosing is suspended;

[0027] And

[0028] Otherwise:

[0029] F(t) = 0.

[0030] Preferably, W(t): warning flag (W ∈ {0, 1}, 0 = no warning, 1 = warning);

[0031]

[0032] Otherwise:

[0033] W(t) = 0.

[0034] Preferably, the high-voltage switchgear communicates with the transformer monitoring unit through optical fiber or wireless private network. The transformer is built-in with an intelligent terminal to collect data such as temperature, oil level, and load current, and forwards it to the high-voltage switchgear;

[0035] The low-voltage switchgear communicates with the transformer and the high-voltage switchgear through Ethernet;

[0036] Coordinated protection of high-voltage switchgear and low-voltage switchgear:

[0037] When the circuit state Si of a certain group of the low-voltage switchgear = 11, the high-voltage switchgear dynamically adjusts the protection setting value:

[0038] Ihigh_set: high-side overcurrent protection setting value;

[0039] Ibase: high-side reference setting value;

[0040] Ilow_max: maximum allowable load current on the low side;

[0041] Ltrans: transformer load rate;

[0042] T: transformer temperature;

[0043] Calculation formula for dynamically adjusting the protection setting value:

[0044]

[0045] Transformer overload warning linkage:

[0046] If the transformer load rate Ltrans ≥ 90%, send a load reduction instruction to the low-voltage switchgear;

[0047] Fault location and isolation:

[0048] When a certain group on the low side Si = 100, the high-voltage switchgear combines the transformer current data to judge the fault area.

[0049] Preferably, the coordination of automatic reclosing and transformer protection:

[0050] When the low-voltage switchgear triggers automatic reclosing (A(t) = 1), the transformer status needs to be verified;

[0051] If the transformer temperature Ttrans > Tmax or the oil level is abnormal, reclosing is prohibited and a warning is triggered;

[0052] If the transformer status is normal, reclosing is allowed and the peak closing current is recorded.

[0053] Preferably, based on the historical overcurrent times Novercurrent of the circuit and the operating times Noperation of the circuit breaker in the low-voltage switchgear, a prediction formula for the life Rlife of the low-voltage circuit in the low-voltage switchgear is made:

[0054]

[0055] The smaller the Rlife index, the lower the remaining life index.

[0056] Compared with the related technology, a power grid equipment communication management system provided by the present invention has the following beneficial effects:

[0057] 1. In the present invention, the high-voltage switchgear is connected to multiple low-voltage switchgears through a ring network wiring method via a transformer, and the overcurrent signals and short-circuit signals of several groups of circuits in the low-voltage switchgear are recorded and analyzed, and automatic closing is realized in cooperation with the automatic reclosing module. After the closing fails within the period, the system is uploaded using the communication module. In the case of multiple overcurrent circuits but no disconnection of the circuit breaker on the low-voltage line of the low-voltage switchgear, circuit maintenance needs to be arranged, which is beneficial to quickly restore power supply in the case of small faults in the power grid. When an abnormality occurs, the abnormal circuit group can be quickly detected, which is beneficial to assisting maintenance personnel to quickly locate the low-voltage circuit group that needs to be repaired.

[0058] 2. The present invention realizes real-time data interaction and collaborative control among the high-voltage switchgear, the transformer, and the low-voltage switchgear, improves the reliability of the system and the fault response speed, optimizes the protection strategy through real-time data sharing, avoids overstepping tripping and misoperation, and avoids the impact of reclosing on the transformer by whether the closing can be completed periodically, thereby prolonging the equipment life. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of the control flow of a power grid equipment communication management system provided by the present invention;

[0060] Figure 2 It is a schematic diagram of the specific implementation 2 of a power grid equipment communication management system provided by the present invention;

[0061] Figure 3 It is a schematic diagram of the specific implementation 3 of a power grid equipment communication management system provided by the present invention. Detailed implementation mode

[0062] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0063] Embodiment 1

[0064] A communication management system for power grid equipment:

[0065] The power grid is connected to the high-voltage switch cabinet, and the high-voltage switch cabinet is connected to the low-voltage switch cabinet through a transformer;

[0066] The high-voltage switch cabinet is connected to multiple low-voltage switch cabinets in a ring network wiring manner through a transformer;

[0067] In each circuit of the low-voltage switch cabinet, a protection module composed of a current transformer, an overcurrent relay, and a circuit breaker is adapted, and a signal module is set for the protection module to record the detection signal of the current transformer, the overcurrent signal of the overcurrent relay, and the disconnection signal of the circuit breaker, and upload the record to the storage unit;

[0068] In several circuits of the low-voltage switch cabinet, signals are recorded in binary. 0 represents that the circuit breaker of this group of circuits is disconnected, 100 represents multiple overcurrent circuits and the circuit breaker is disconnected, 1 represents that the circuit breaker of this group of circuits is not disconnected, and 11 represents multiple overcurrent circuits but the circuit breaker is not disconnected;

[0069] Automatic reclosing module: An automatic reclosing module is set in the high-voltage switch cabinet. When the signal uploaded by the signal module of the low-voltage switch cabinet is "0" or "100", the automatic reclosing module is started. If the reclosing fails twice within one cycle, the automatic reclosing module is suspended;

[0070] Communication module: When the automatic reclosing module is suspended, it is uploaded to the system through the communication module, and the system notifies the maintenance;

[0071] Early warning module: When the low-voltage switch cabinet uploads a signal of "11", it is uploaded to the system to remind that there is a risk in the circuit with the "11" signal in the low-voltage switch cabinet.

[0072] Among them, N: the number of circuits in the low-voltage switch cabinet;

[0073] T: the automatic reclosing cycle time;

[0074] K: the automatic reclosing attempt times counter (k ∈ {0, 1, 2});

[0075] Circuit status signal: Si(t): The status signal of the i-th group of circuits at time t (Si ∈ {0, 1, 11, 100}, i = 1, 2,..., N);

[0076] Signal meaning:

[0077] Si = 0: Circuit breaker is open;

[0078] Si = 1: Circuit breaker is closed and there is no overcurrent;

[0079] Si = 11: Circuit breaker is closed, but multiple overcurrents are detected;

[0080] Si = 100: Circuit breaker is open and multiple overcurrents are detected;

[0081] A(t): Automatic reclosing trigger flag (A ∈ {0, 1}, 0 = not triggered, 1 = triggered);

[0082] F(t): Automatic reclosing failure flag (F ∈ {0, 1}, 0 = not failed, 1 = failed);

[0083] Automatic reclosing trigger condition:

[0084] When there is at least one group of circuits that meets the following conditions, automatic reclosing is triggered;

[0085]

[0086] Otherwise: A(t) = 0.

[0087] Among them, automatic reclosing failure determination:

[0088] If two consecutive closing failures occur within a period T, automatic reclosing is suspended;

[0089] And

[0090] Otherwise:

[0091] F(t) = 0.

[0092] Among them, W(t): Warning flag (W ∈ {0, 1}, 0 = no warning, 1 = warning);

[0093]

[0094] Otherwise:

[0095] W(t) = 0.

[0096] In the actual application scenario:

[0097] Scenario 1: The circuit breaker of Group 3 is open and there is no overcurrent (S3 = 0), and other circuits are normal (Si = 1).

[0098] The automatic reclosing is triggered (A = 1). If the reclosing fails twice, then F = 1 and the communication is triggered (C = 1).

[0099] Scenario 2: The circuit breaker of Group 5 is closed but there are multiple overcurrents (S5 = 11).

[0100] The warning module is triggered (W = 1W = 1) to prompt the risk.

[0101] Scenario 3: The circuit breaker of Group 2 is open and there are multiple overcurrents (S2 = 100).

[0102] The automatic reclosing is triggered (A = 1). If the reclosing is successful once, the counter is reset (k = 0).

[0103] Among them, the high-voltage switchgear communicates with the transformer monitoring unit through optical fiber or wireless private network. The transformer is built-in with an intelligent terminal to collect data such as temperature, oil level, and load current, and forward it to the high-voltage switchgear;

[0104] The low-voltage switchgear communicates with the transformer and the high-voltage switchgear through Ethernet;

[0105] Among them, the communication protocol:

[0106] Adopt the IEC 61850 standard to define a unified data model (such as LN: LogicalNode) and services (such as GOOSE, SV) to achieve interoperability of heterogeneous devices.

[0107] To improve communication security and fault tolerance;

[0108] Dual-channel redundant communication can be adopted:

[0109] A main and standby dual-channel (such as optical fiber + wireless) is adopted between the high-voltage switchgear and the transformer and the low-voltage switchgear to automatically switch the faulty link.

[0110] Data encryption and signature:

[0111] Use AES-256 to encrypt communication data and digitally sign control instructions (such as tripping, reclosing) to prevent malicious tampering.

[0112] Heartbeat detection and timeout retransmission:

[0113] Define the heartbeat interval as 1s. If no heartbeat packet is received continuously for 3 times, it is determined that the device is offline and a warning is triggered.

[0114] Example:

[0115] The high-voltage switchgear sends circuit breaker status (XCBR) and fault current (MMXU) data;

[0116] The transformer sends temperature (YPTR) and load rate (MMTR);

[0117] The low-voltage switchgear sends circuit status signals (Si) and early warning signs (W).

[0118] Coordinated protection between high-voltage switchgear and low-voltage switchgear:

[0119] When the circuit status Si of a certain group in the low-voltage switchgear is 11, the high-voltage switchgear dynamically adjusts the protection setting value:

[0120] Ihigh_set: Overcurrent protection setting value on the high-voltage side;

[0121] Ibase: Reference setting value on the high-voltage side;

[0122] Ilow_max: Maximum allowable load current on the low-voltage side;

[0123] Ltrans: Transformer load rate;

[0124] T: Transformer temperature;

[0125] Calculation formula for dynamic adjustment of protection setting value:

[0126]

[0127] Transformer overload early warning linkage:

[0128] If the transformer load rate Ltrans ≥ 90%, a load reduction instruction is sent to the low-voltage switchgear;

[0129] Fault location and isolation:

[0130] When Si of a certain group on the low-voltage side is 100, the high-voltage switchgear combines transformer current data to judge the fault area.

[0131] Thus, maintenance can be notified through the management system.

[0132] Scenario 4

[0133] If Si of a certain group on the low-voltage side = 11 (multiple overcurrents), and N = 10, Ilow max = 50A, then the setting value on the high-voltage side is increased to:

[0134] Ihigh set = max(800A, 10 × 50A) = 800A (not exceeding the limit)

[0135] If multiple groups of circuits are overcurrent and the sum exceeds Ibase, the protection threshold is dynamically adjusted.

[0136] Among them, the coordination between the automatic reclosing and the transformer protection:

[0137] When the low-voltage switchgear triggers the automatic reclosing (A(t) = 1), the transformer status needs to be verified;

[0138] If the transformer temperature Ttrans > Tmax or the oil level is abnormal, reclosing is prohibited and a warning is triggered;

[0139] If the transformer status is normal, reclosing is allowed and the peak closing current is recorded.

[0140] Among them, for the life of the low-voltage circuit in the low-voltage switchgear, a prediction formula for the low-voltage circuit life Rlife is made through the historical overcurrent times Novercurrent of the circuit and the breaker operation times Noperation:

[0141]

[0142] The smaller the Rlife index, the lower the remaining life index.

[0143] In the actual application scenario:

[0144] Scenario 5: The overcurrent on the low-voltage side causes the protection on the high-voltage side to act in cascade;

[0145] For a certain group Si = 11 in the low-voltage switchgear, after the high-voltage switchgear receives the signal, it raises the protection setting value from Ibase = 800A to Ihigh set = 1000A to avoid overstepping tripping.

[0146] Scenario 6: The overload of the transformer triggers the load reduction on the low-voltage side;

[0147] The transformer load rate Ltrans = 95%, and the low-voltage switchgear automatically cuts off the non-critical load and reduces it to Ltrans = 85%.

[0148] Scenario 7: Fault tolerance processing under communication interruption;

[0149] When the high-voltage switchgear detects that the heartbeat of the low-voltage switchgear times out, it switches to the standby communication channel and records the event log

[0150] Illustrative example:

[0151] For a certain circuit, the historical overcurrent times Novercurrent = 5 and the breaker operation times Noperation = 100, then:

[0152]

[0153] The remaining life index is extremely low and immediate maintenance is required.

[0154] Embodiment 2

[0155] When a circuit breaker in a low-voltage switchgear cabinet disconnects for a certain low-voltage circuit, the automatic reclosing module is activated, and the transformer status is verified preferentially. If the transformer temperature is normal, the closing operation is performed. If the transformer temperature Ttrans > Tmax or the oil level is abnormal, reclosing is prohibited and a warning is triggered, and the short-circuit signal is uploaded to the management system through the communication module to notify regular maintenance.

[0156] Embodiment 3

[0157] When a circuit breaker in a low-voltage switchgear cabinet disconnects for a certain low-voltage circuit, the automatic reclosing module is activated to perform automatic closing on this circuit. If the closing fails twice within one cycle, the automatic reclosing module is suspended; the system is notified through the communication module for maintenance.

[0158] Embodiment 4

[0159] The difference between this Embodiment 2 and Embodiment 3 is that if the low-voltage circuit in Embodiment 2 and Embodiment 3 has had overcurrent or short-circuit conditions multiple times, then the life of this low-voltage circuit needs to be predicted;

[0160] If the Rlife index is less than 2, timely maintenance is required and some lines of the low-voltage circuit need to be replaced.

[0161] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A power grid equipment communication management system, characterized in that: The high-voltage switchgear is connected to the grid, and the high-voltage switchgear is connected to the low-voltage switchgear through a transformer; The high-voltage switchgear is connected to multiple low-voltage switchgears by means of ring network connection through transformers; A protection module consisting of a current transformer, an overcurrent relay and a circuit breaker is adapted to each circuit of the low-voltage switch cabinet, and a signal module is set for the protection module to record the detection signal of the current transformer, the overcurrent signal of the overcurrent relay and the disconnection signal of the circuit breaker, and upload the record to the storage unit; Binary recording signals are used in several groups of circuits in the low-voltage switch cabinet. 0 represents that the circuit breaker of this group of circuits is disconnected, 100 represents that the circuit has been overcurrent multiple times and the circuit breaker is disconnected, 1 represents that the circuit breaker of this group of circuits is not disconnected, and 11 represents that the circuit has been overcurrent multiple times but the circuit breaker is not disconnected. Automatic reclosing module: An automatic reclosing module is set in the high-voltage switch cabinet. When the signal uploaded by the signal module of the low-voltage switch cabinet is "0" or "100", the automatic reclosing module is started. If the closing fails twice within one cycle, the automatic reclosing module is suspended. Communication module: When the automatic reclosing module is suspended, the system is uploaded through the communication module, and the system notifies maintenance; Early warning module: If the upload signal in the low-voltage switch cabinet is "11", it will be uploaded to the system to remind that the circuit with the "11" signal in the low-voltage switch cabinet is at risk.

2. A power grid equipment communication management system according to claim 1, characterized in that: N: number of circuit groups in the low-voltage switchgear; T: automatic reclosing cycle time; K: counter of automatic reclosing attempts (k∈{0,1,2}); Circuit state signal: Si(t): the state signal of the i-th group of circuits at time t (Si∈{0,1,11,100}, i=1,2,...,N); A(t): automatic reclosing trigger flag (A∈{0,1}, 0=not triggered, 1=triggered); F(t): automatic reclosing failure flag (F∈{0,1}, 0=not failed, 1=failed); Automatic reclosing trigger conditions: When there is at least one set of circuits that meet the following conditions, the automatic reclosing is triggered; Otherwise: A(t)=0.

3. A power grid equipment communication management system according to claim 2, characterized in that: Automatic reclosing failure judgment: If the closing fails twice in a row within a period T, the automatic reclosing will be suspended; and otherwise: F(t)=0.

4. A power grid equipment communication management system according to claim 1, characterized in that: W(t): warning flag (W∈{0,1}, 0=no warning, 1=warning); otherwise: W(t)=0.

5. A power grid equipment communication management system according to claim 1, characterized in that: The high-voltage switchgear communicates with the transformer monitoring unit through optical fiber or wireless private network. The transformer has a built-in intelligent terminal to collect data such as temperature, oil level, load current, etc., and forward it to the high-voltage switchgear; The low-voltage switchgear communicates with the transformer and high-voltage switchgear via Ethernet; Coordinated protection of high-voltage switchgear and low-voltage switchgear: When the circuit status Si of a group of low-voltage switch cabinet is 11, the high-voltage switch cabinet dynamically adjusts the protection setting value: Ihigh_set: high-voltage side overcurrent protection setting; Ibase: high-voltage side reference value; Ilow_max: Maximum allowable load current on the low voltage side; Ltrans: Transformer load rate; T: transformer temperature; Dynamic protection setting adjustment calculation formula: Transformer overload warning linkage: If the transformer load rate Ltrans ≥ 90%, a load reduction instruction is sent to the low-voltage switchgear; Fault location and isolation: When Si=100 for a group on the low-voltage side, the high-voltage switchgear determines the fault area based on the transformer current data.

6. A power grid equipment communication management system according to claim 4, characterized in that: Coordination between automatic reclosing and transformer protection: When the low-voltage switchgear triggers the automatic reclosing (A(t)=1), the transformer status needs to be verified; If the transformer temperature Ttrans>Tmax or the oil level is abnormal, reclosing is prohibited and a warning is triggered; If the transformer is in normal condition, reclosing is allowed and the peak value of closing current is recorded.

7. A power grid equipment communication management system according to claim 4, characterized in that: Through the historical overcurrent times Novercurrent and the circuit breaker operation times Norperation, a prediction formula for the life of the low-voltage circuit in the low-voltage switchgear is made: The smaller the Rlife index is, the lower the remaining life index is.

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