Switch cabinet partial discharge sensor time synchronization method and system, and storage medium

Abstract

The invention discloses a switch cabinet partial discharge sensor time synchronization method and system and a storage medium. A monitoring host sends a time service signal to a sensor; the sensor estimates propagation time delay, determines response time delay and calculates a propagation time delay error; through multiple times of communication between the host and the sensor, response time delay is eliminated, the time error of time service data between the host and the sensor is calculated, the time error is eliminated, and time synchronization is achieved. Time synchronization is achieved through inherent delay data of the monitoring host and the sensor, and the method is stable and reliable and is not affected by the external environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of substation partial discharge detection, and relates to a time synchronization method, system and storage medium for a partial discharge sensor of a switch cabinet. Background Technique

[0002] The phenomenon of partial discharge is a sign of insulation deterioration of power equipment. Conducting partial discharge detection on equipment and detecting the discharge source accurately and early can prevent accidents and ensure the safe and reliable operation of the power system. Ultra-high frequency detection methods, high-frequency current detection methods, etc. can be used for live detection and online monitoring without power interruption, can detect internal insulation defects of power equipment, and can give early warnings of insulation faults of power equipment, and are gradually applied and promoted in the live detection and online monitoring of partial discharge of power equipment.

[0003] If there are problems in the process of early manufactured or installed ring main units, it will lead to uneven electric field distribution in some areas of the insulation system, or during the later operation process, affected by factors such as vibration, temperature and humidity, the insulation in some areas ages, then partial discharge is very likely to occur at these weak insulation positions. For the data upload of partial discharge, it is generally required that the data contains a time stamp accurate to the time, which is of great significance for tracing the accident after the fault.

[0004] At present, the partial discharge monitoring sensors of switch cabinets generally collect data regularly and upload the data to the background wirelessly. Since the sensor itself does not have a time service function, after its time is initialized, it will rely on the crystal oscillator carried by the sensor to generate a real-time clock. Since the frequency of the crystal oscillator is affected by the environment, its long-term operation will cause clock offset, resulting in a large deviation in the time reference of the sensor and affecting the inaccuracy of the time information of the monitoring data. Summary of the Invention

[0005] The purpose of the present invention is to provide a time synchronization method, system and storage medium for a partial discharge sensor of a switch cabinet, which uses the monitoring host and the inherent delay data of the sensor itself to achieve time synchronization, and the method is stable and reliable and not affected by the external environment.

[0006] The technical solution to achieve the purpose of the present invention is as follows:

[0007] A time synchronization method for a partial discharge sensor of a switch cabinet includes the following steps:

[0008] S01: The monitoring host sends a time service signal to the sensor;

[0009] S02: The sensor estimates the propagation delay, determines the response delay, and calculates the propagation delay error;

[0010] S03: Through multiple communications between the host and the sensor, eliminate the response time delay, calculate the time error of the timing data between the host and the sensor, eliminate the time error, and achieve time synchronization.

[0011] In the preferred technical solution, the sensor estimating the propagation delay in step S02 includes:

[0012] The local time of the sensor clock is expressed as a function γ(t) of the real event:

[0013] γ(t) = (1 + δ)t + μ

[0014] In the formula, δ is the clock drift; μ is the clock offset;

[0015] The monitoring host sends a timing signal at the local time γ A (t1), and the sensor receives the signal at the local time γ B (t2). The propagation delay estimated by the sensor is:

[0016] τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μ B -μ A

[0017] In the formula: τ1 = t2 - t1 is the real propagation delay, including the sending time, access time, propagation time and receiving time, t2 and t1 are different moments, δ A 、δ B are respectively the clock drifts of the monitoring host and the sensor, μ A 、μ B are respectively the clock offsets of the monitoring host and the sensor, and τ0 is the estimated propagation delay.

[0018] In the preferred technical solution, calculating the propagation delay error includes:

[0019] The sensor returns a response signal after the time delay τ2, and calculates the return time τ3 determined according to the monitoring host clock:

[0020]

[0021] The round-trip propagation delay estimated by the monitoring host is:

[0022]

[0023] The propagation delay error is:

[0024]

[0025] In the preferred technical solution, eliminating the response time delay in step S03 includes:

[0026] After the delay amount is equal to the response delay determined by its clock the sensor sends an even number of response signals again;

[0027] The monitoring host receives the return time as:

[0028]

[0029] To eliminate the response time delay, the estimated propagation time delay is:

[0030]

[0031] In the preferred technical solution, calculating the time error δ A τ1 of the timing data between the host and the sensor in step S03.

[0032] The present invention also discloses a time synchronization system for a partial discharge sensor of a switch cabinet, including:

[0033] A timing signal sending module, where the monitoring host sends a timing signal to the sensor;

[0034] A propagation time delay error calculation module, where the sensor estimates the propagation time delay, determines the response time delay, and calculates the propagation time delay error;

[0035] A time synchronization module, through multiple communications between the host and the sensor, eliminates the response time delay, calculates the time error of the timing data between the host and the sensor, eliminates the time error, and realizes time synchronization.

[0036] In the preferred technical solution, the sensor estimating the propagation time delay in the propagation time delay error calculation module includes:

[0037] The local time of the sensor clock is expressed as a function γ(t) of the real event:

[0038] γ(t) = (1 + δ)t + μ

[0039] In the formula, δ is the clock drift; μ is the clock offset;

[0040] The monitoring host sends a timing signal at the local time γ A (t1), and the sensor receives the signal at the local time γ B (t2). The propagation time delay estimated by the sensor is:

[0041] τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μB -μ A

[0042] where: τ1 = t2 - t1 is the true propagation delay, including the transmission time, access time, propagation time, and reception time, t2 and t1 are different moments, δ A , δ B are the clock drifts of the monitoring host and the sensor respectively, μ A , μ B are the clock offsets of the monitoring host and the sensor respectively, and τ0 is the estimated propagation delay.

[0043] In the preferred technical solution, calculating the propagation delay error includes:

[0044] The sensor returns a response signal after a delay of τ2, and calculates the return time τ3 determined according to the monitoring host clock:

[0045]

[0046] The estimated round-trip propagation delay through the monitoring host is:

[0047]

[0048] The propagation delay error is:

[0049]

[0050] In the preferred technical solution, eliminating the response delay in the time synchronization module includes:

[0051] After the delay amount is equal to the response delay determined by its clock , the sensor sends an even number of response signals again;

[0052] The monitoring host receives the return time as:

[0053]

[0054] Eliminating the response delay, the estimated propagation delay is:

[0055]

[0056] The present invention also discloses a computer storage medium, on which a computer program is stored, and when the computer program is executed, the above-mentioned time synchronization method for the partial discharge sensor of the switch cabinet is realized.

[0057] Compared with the prior art, the present invention has the following remarkable advantages:

[0058] 1. By monitoring the parameters of the host and the data exchange between the monitoring host and the sensor, the present invention realizes the accurate calculation of the timing error of the switchgear partial discharge monitoring sensor network, overcoming the problem that it is difficult to accurately synchronize the time of the current switchgear partial discharge Internet of Things sensors. Using the inherent delay data of the monitoring host and the sensor itself to achieve time synchronization, the method is stable and reliable, not affected by the external environment, and has practical significance and value.

[0059] 2. It is realized based on multiple data exchanges between the monitoring host and the sensor, with simple operation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is the flowchart of the switchgear partial discharge sensor time synchronization method of this embodiment;

[0061] Figure 2 is the schematic diagram of the monitoring host timing the partial discharge sensor in an embodiment;

[0062] Figure 3 is the decomposition of the time delay of the timing data packet from the monitoring host to the partial discharge sensor;

[0063] Figure 4 is the schematic diagram of the sensor returning the response signal twice. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0064] The principle of the present invention is: on the basis of determining the response delay, through multiple communications between the host and the partial discharge sensor, the time error of the timing data between the host and the sensor is calculated to achieve the time synchronization between the sensor and the host.

[0065] Embodiment 1:

[0066] As Figure 1 shown, a switchgear partial discharge sensor time synchronization method includes the following steps:

[0067] S01: The monitoring host sends a timing signal to the sensor;

[0068] S02: The sensor estimates the propagation delay, determines the response delay, and calculates the propagation delay error;

[0069] S03: Through multiple communications between the host and the sensor, the response delay is eliminated, the time error of the timing data between the host and the sensor is calculated, the time error is eliminated, and time synchronization is achieved.

[0070] In a preferred embodiment, in step S02, the sensor estimating the propagation delay includes:

[0071] The local time of the sensor clock is expressed as a function γ(t) of the real event:

[0072] γ(t) = (1 + δ)t + μ

[0073] Where δ is the clock drift; μ is the clock offset;

[0074] The monitoring host sends a time synchronization signal at the local time γ A (t1), and the sensor receives the signal at the local time γ B (t2). The propagation delay estimated by the sensor is:

[0075] τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μ B -μ A

[0076] Where: τ1 = t2 - t1 is the true propagation delay, including the transmission time, access time, propagation time, and reception time. t2 and t1 are different times, and δ A 、δ B are the clock drifts of the monitoring host and the sensor respectively, and μ A 、μ B are the clock offsets of the monitoring host and the sensor respectively, and τ0 is the estimated propagation delay.

[0077] In a preferred embodiment, calculating the propagation delay error includes:

[0078] The sensor returns a response signal after a delay of τ2, and calculates the return time τ3 determined according to the monitoring host's clock:

[0079]

[0080] The round-trip propagation delay estimated by the monitoring host is:

[0081]

[0082] The propagation delay error is:

[0083]

[0084] In a preferred embodiment, eliminating the response delay in step S03 includes:

[0085] After the delay amount is equal to the response delay determined by its clock the sensor sends an even number of response signals again;

[0086] The return time received by the monitoring host is:

[0087]

[0088] To eliminate the response time delay, the estimated propagation time delay is as follows:

[0089]

[0090] In a preferred embodiment, the time error δ A τ1 between the timing data of the master and the sensor is calculated in step S03.

[0091] In another embodiment, a computer storage medium stores a computer program, and when the computer program is executed, the above-mentioned time synchronization method for the partial discharge sensor of the switch cabinet is implemented. The above method is not elaborated here.

[0092] In another embodiment, a time synchronization system for the partial discharge sensor of the switch cabinet includes:

[0093] A timing signal sending module, the monitoring master sends a timing signal to the sensor;

[0094] A propagation time delay error calculation module, the sensor estimates the propagation time delay, determines the response delay, and calculates the propagation time delay error;

[0095] A time synchronization module, through multiple communications between the master and the sensor, eliminates the response time delay, calculates the time error between the timing data of the master and the sensor, eliminates the time error, and realizes time synchronization.

[0096] Specifically, taking a preferred embodiment as an example, the working process of the time synchronization system for the partial discharge sensor of the switch cabinet is described as follows:

[0097] As Figure 2 shown, the partial discharge monitoring system of the switch cabinet generally includes: an Internet of Things sensor and a monitoring master. The former is generally installed on the cabinet door of the switch cabinet, and the latter is usually installed at the entrance of the distribution room or the central control room. The sensor and the monitoring master communicate with each other wirelessly through Lora, WiFi, etc.

[0098] The monitoring master and the sensor communicate with each other, and the sent data packet contains a timestamp, which is based on the time of the master (derived from network timing or GPS timing, which is relatively easy to implement). The sensor receives the timing data packet (including the master time and time error, etc.).

[0099] The local time of the sensor clock can be expressed as a function γ(t) of the real event, where for an accurate clock γ(t) = t. In a short time interval, γ(t) can be modeled as:

[0100] γ(t) = (1 + δ)t + μ (1)

[0101] where δ is the clock drift; μ is the clock offset; the clock drift affects the time interval.

[0102] If the time delay to be generated by the sensor is τ d , then the actual time delay generated is:

[0103]

[0104] Suppose the monitoring host A sends a timing signal at the local time γ A (t1), and the sensor B receives the signal at the local time γ B (t2). The estimated propagation delay of the sensor B is:

[0105] τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μ B -μ A (3)

[0106] where: τ1 = t2 - t1 is the true propagation delay, including the transmission time, access time, propagation time and reception time, as Figure 3 shown. δ A , δ B are the clock drifts of the monitoring host and the sensor respectively. μ A , μ B are the clock offsets of the monitoring host and the sensor respectively. τ0 is the estimated propagation delay.

[0107] The clock drift affects the observable value of the time interval. If the measurement time interval of a single sensor is:

[0108] τ = t2 - t1, then according to formula (1), the estimated time interval is:

[0109]

[0110] That is to say, if the sensor needs to generate a time delay τ d , then due to the influence of clock drift and time offset, the actual time delay generated is:

[0111]

[0112] The sensor B returns a response signal after the time delay τ2.

[0113] According to formula (5), its actual response time delay is:

[0114]

[0115] If τ1 is the delay decomposition of the monitoring host sending data packets to the sensor (assuming here that the processors of the monitoring host and the sensor are the same, then the transmission time, reception time, and other parameters of the monitoring host and the partial discharge sensor are the same), then Figure 3 it can be obtained that:

[0116] τ1 = transmission time + access time + propagation time + reception time

[0117] The round-trip time from the host sending data to the host receiving data is 2τ1. is the response delay of the sensor. The estimated round-trip time from the host sending data to the host receiving data is 2τ0 (equivalent to τ3).

[0118] According to formula (4), the round-trip time τ3 estimated by the clock of host A can be calculated as:

[0119]

[0120] From formula (6) and formula (7), it can be obtained that

[0121]

[0122] In the absence of other information, the round-trip propagation delay of the synchronized data estimated by host A is:

[0123]

[0124] It can be seen that the propagation delay error is:

[0125]

[0126] In the above formula, τ1 is the true propagation delay, and τ0 is the estimated propagation delay.

[0127] It can be seen from the above formula that the error is mainly determined by the propagation delay and the response delay.

[0128] To further reduce the error, the second term in formula (10) can be eliminated, that is, after the delay amount is equal to the response delay determined by its clock the sensor sends a response signal again (or an even number of times, such as 2, 4, 6, etc.), as follows Figure 4 shown.

[0129] When the sensor sends the second reply signal, the return time received by the host is:

[0130]

[0131] According to formula (8) and formula (11), the designed response delay term can be eliminated, then

[0132]

[0133] As known from the foregoing, in the host δ A It is determined that as long as τ1 is calculated, the time accuracy error of timing from the host to the sensor can be calculated, and precise timing of the sensor can be achieved.

[0134] Specific examples are as follows:

[0135] Such as Figure 1 In, by monitoring the host to time the partial discharge sensor, the set parameters are:

[0136] δ A = 0.001, δ B = 0.002, c = 3×10 8 m / s, τ2 = 10 -8 s

[0137] Assume that the actual propagation distance from the sensor to the host is d = 5m, and the electromagnetic wave signal propagates at the speed of light. Then, the timing error can be calculated by this method as Thus, the timing error between the sensor and the monitoring host can be eliminated, and then precise time synchronization of multiple sensor monitoring networks can be achieved.

[0138] In practical applications, generally, the true distance between the monitoring host and the sensor is unknown. Through two timing responses of the sensor, the monitoring host will receive two timestamps, and then the timing error can be calculated. Then, in the case where the monitoring host is the standard time, by timing from it to the sensor and eliminating the time error, high-precision time synchronization between the two can be achieved.

[0139] This method realizes the precise calculation of the timing error of the switch cabinet partial discharge monitoring sensor network by monitoring the host parameters and the data exchange between the monitoring host and the sensor. The method is stable and reliable, not affected by the external environment, and has good practical significance and value.

[0140] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A time synchronization method for partial discharge sensors of switchgear, characterized in that It includes the following steps: S01: The monitoring host sends a timing signal to the sensor; S02: The sensor estimates the propagation delay, determines the response delay, and calculates the propagation delay error; S03: Through multiple communications between the host and the sensor, the response delay is eliminated, the time error of the timing data between the host and the sensor is calculated, the time error is eliminated, and time synchronization is achieved.

2. The method for time synchronization of the partial discharge sensor of the switchgear cabinet according to claim 1, characterized in that In step S02, the sensor's estimation of the propagation delay includes: The local time of the sensor clock is expressed as a function γ(t) of the real event: γ(t) = (1 + δ)t + μ In the formula, δ is the clock drift; μ is the clock offset; The monitoring host is at local time γ A (t1) emits a time signal, and the sensor receives the signal at local time γ B (t2). The propagation delay estimated by the sensor is: τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μ B -μ A where: τ1 = t2 - t1 is the true propagation delay, including transmission time, access time, propagation time, and reception time, t2 and t1 are different moments, δ A , δ B are the clock drifts of the monitoring host and the sensor respectively, μ A , μ B are the clock offsets of the monitoring host and the sensor respectively, and τ0 is the estimated propagation delay.

3. The method for time synchronization of the partial discharge sensor of the switchgear cabinet according to claim 2, characterized in that Calculating the propagation delay error includes: The sensor returns a response signal after a delay τ2, and calculates the return time τ3 determined according to the monitoring host clock: The round-trip propagation delay estimated by the monitoring host is: The propagation delay error is:

4. The method for time synchronization of the partial discharge sensor of the switch cabinet according to claim 3, characterized in that In step S03, eliminating the response delay includes: After the delay amount equals the response delay determined by its clock the sensor sends an even number of response signals again; The return time received by the monitoring host is: After eliminating the response delay, the estimated propagation delay is:

5. The method for time synchronization of the partial discharge sensor of the switchgear cabinet according to claim 4, wherein, In step S03, the time error δ of the timing data between the host and the sensor is calculated as A τ1.

6. A time synchronization system for partial discharge sensors of a switchgear, characterized in that, It includes: A timing signal sending module, where the monitoring host sends a timing signal to the sensor; A propagation delay error calculation module, where the sensor estimates the propagation delay, determines the response delay, and calculates the propagation delay error; A time synchronization module, through multiple communications between the host and the sensor, eliminates the response delay, calculates the time error of the timing data between the host and the sensor, eliminates the time error, and achieves time synchronization.

7. The partial discharge sensor time synchronization system for switchgear according to claim 6, wherein In the propagation delay error calculation module, the sensor's estimation of the propagation delay includes: The local time of the sensor clock is expressed as a function γ(t) of the real event: γ(t) = (1 + δ)t + μ In the formula, δ is the clock drift; μ is the clock offset; The monitoring host at local time γ A (t1) emits a time signal, and the sensor receives the signal at local time γ B (t2). The propagation delay estimated by the sensor is: τ0 = γ B (t2) - γ A (t1) = τ1 + δ B t2 - δ A t1 + μ B -μ A Where: τ1 = t2 - t1 is the true propagation delay, including transmission time, access time, propagation time, and reception time, t2 and t1 are different times, and δ A , δ B are the clock drifts of the monitoring host and the sensor respectively, μ A , μ B are the clock offsets of the monitoring host and the sensor respectively, and τ0 is the estimated propagation delay.

8. The partial discharge sensor time synchronization system for switchgear according to claim 7, characterized in that, Calculating the propagation delay error includes: The sensor returns a response signal after a delay τ2, and calculates the return time τ3 determined according to the monitoring host clock: The round-trip propagation delay estimated by the monitoring host is: The propagation delay error is:

9. The partial discharge sensor time synchronization system for switchgear according to claim 8, wherein In the time synchronization module, eliminating the response delay includes: After the delay amount equals the response delay determined by its clock the sensor sends an even number of response signals again; The return time received by the monitoring host is: After eliminating the response delay, the estimated propagation delay is:

10. A computer storage medium, on which a computer program is stored, characterized in that, When the computer program is executed, it implements the time synchronization method for the partial discharge sensor of the switchgear cabinet described in any one of claims 1-5.

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