DEFECT MONITORING APPARATUS AND DETECTION METHOD FOR TRANSFORMER OIL CONSERVATOR BASED ON EDGE COMPUTING

Abstract

Disclosed are a defect monitoring apparatus and detection method for a transformer oil conservator based on edge computing. The monitoring apparatus includes: a sensing terminal, an edge intelligent gateway, a monitoring terminal, an oil conservator defect monitoring cloud platform, and a client terminal. The edge intelligent gateway and the monitoring terminal are both disposed in a substation. The monitoring terminal is configured to access the edge intelligent gateway. The sensing terminal includes: an airflow sensor, an oil temperature sensor, an ambient temperature sensor, and a microwave oil level measurement assembly. The sensing terminal sends detection data information to the edge intelligent gateway, and the edge intelligent gateway stores and determines a category of the detection data information. The present disclosure can recognize capsule damage, partial blockage of a breathing circuit, leakage in the breathing circuit, moisture impurities in a breathing tube, and false oil level.

Claims

1. A defect monitoring apparatus for a transformer oil conservator based on edge computing, comprising: a sensing terminal, an edge intelligent gateway, a monitoring terminal, an oil conservator defect monitoring cloud platform, and a client terminal, wherein the edge intelligent gateway and the monitoring terminal are both disposed in a substation; the monitoring terminal is configured to access the edge intelligent gateway; the sensing terminal comprises: an airflow sensor (5), an oil temperature sensor (6), an ambient temperature sensor (7), and a microwave oil level measurement assembly; the airflow sensor (5) is disposed on a breathing tube (3), and is configured to measure a breathing airflow rate of an oil conservator (1); the oil temperature sensor (6) is disposed at a lower portion of a side of the oil conservator (1), and a probe of the oil temperature sensor (6) extends into the oil conservator (1) and is immersed in transformer oil; the oil temperature sensor (6) is configured to measure an oil temperature of the oil conservator; the ambient temperature sensor (7) is disposed outside the oil conservator (1); the ambient temperature sensor (7) is configured to measure an ambient temperature; the microwave oil level measurement assembly is disposed at a top of an inner wall of the oil conservator (1), and the microwave oil level measurement assembly is away from a capsule (2); the microwave oil level measurement assembly is configured to measure a height of an oil level of the oil conservator; and the sensing terminal is configured to send detection data to the edge intelligent gateway, and an original oil level gauge (8) of the oil conservator is configured to send data information thereof to the edge intelligent gateway; the edge intelligent gateway is configured to store and evaluate the detection data, and send an evaluation result indicating a defect and corresponding data to the oil conservator defect monitoring cloud platform; and the oil conservator defect monitoring cloud platform is configured to send an alarm command to the client terminal.

2. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the microwave oil level measurement assembly comprises: a microwave transmitting antenna (9) and a microwave receiving antenna (10); the microwave transmitting antenna (9) and the microwave receiving antenna (10) are both oriented towards the oil face, upper ends of the microwave transmitting antenna (9) and the microwave receiving antenna (10) are both fastened at the top of the inner wall of the oil conservator (1), and a transmitting end of the microwave transmitting antenna (9) is located in a same horizontal plane with a receiving end of the microwave receiving antenna (10).

3. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the sensing terminal communicates with the edge intelligent gateway through a ZigBee network; the edge intelligent gateway communicates with the monitoring terminal through the ZigBee network; and the edge intelligent gateway communicates with the oil conservator defect monitoring cloud platform through a General Packet Radio Service (GPRS) network.

4. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the airflow sensor (5) is disposed close to a dehydrating breather (4).

5. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the airflow sensor (5) is configured to adopt bidirectional airflow rate measurement, with a measurement range of −200 slpm to +200 slpm, a total error band less than or equal to 3% of a reading, and a response time less than or equal to 1 ms.

6. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the oil temperature sensor (6) and the ambient temperature sensor (7) are both platinum resistance sensors, with a measurement range of −40° C. to 120° C. and accuracy of ±0.5° C.

7. The defect monitoring apparatus for a transformer oil conservator based on edge computing according to claim 1, wherein the edge intelligent gateway is configured to adopt an ARM Cortex-A7 processor, with 1 GB RAM and 8 GB Embedded Multi Media Card (eMMC); and the client terminal is a personal computer (PC), a tablet computer, or a smart phone.

8. A defect detection method for a transformer oil conservator based on edge computing, comprising the following steps: S1: monitoring, by a sensing terminal, the following data in real time: a breathing airflow rate of an oil conservator, an oil temperature of the oil conservator, an ambient temperature, a microwave transmitting power, and a microwave receiving power; S2: determining whether the oil conservator has a false oil level defect: calculating an actual oil level height D.sub.1 according to the microwave transmitting power and the microwave receiving power; sending, by an original oil level gauge (8) of the oil conservator, data information to an edge intelligent gateway; calculating, by the edge intelligent gateway, a difference between the actual oil level height D.sub.1 and a display value D of the original oil level gauge (8) of the oil conservator; and when the difference is greater than 3 cm, determining that the oil conservator has a false oil level defect; otherwise, determining that the oil conservator has no false oil level defect; S3: sampling real-time monitoring data, to form a breathing airflow rate curve; when a change in the ambient temperature is within 10° C. and a change in the oil temperature of the oil conservator is within 4° C., comparing a peak breathing airflow rate V.sub.m of the oil conservator monitored in real time with an average peak breathing airflow rate V.sub.a of the oil conservator in the passing month under the same condition; if a difference is greater than or equal to 15%, performing step S4; otherwise, determining that the following four types of defects do not exist: capsule damage, partial blockage of a breathing circuit, leakage in the breathing circuit, or moisture impurities in a breathing tube; S4: when V.sub.m≥1.2V.sub.a, t.sub.h≤0.9t.sub.ha, and t.sub.x≤0.9t.sub.xa, determining that a capsule damage defect exists; wherein t.sub.h is a single expiration duration monitored in real time, t.sub.x is a single inhalation duration monitored in real time, t.sub.ha is an average single expiration duration in the passing month, and t.sub.xa is an average single inhalation duration in the passing month; when V.sub.m≤0.8V.sub.a, t.sub.h≥1.1t.sub.ha, and t.sub.x≥1.1t.sub.xa, determining that a defect of partial blockage of the breathing circuit exists; when V.sub.m≤0.8V.sub.a, |t.sub.h−t.sub.ha|<0.05t.sub.ha, and |t.sub.x−t.sub.xa|<0.05t.sub.xa, determining that a defect of leakage in the breathing circuit exists; and when V.sub.m≤0.85V.sub.a and an airflow rate zero-crossing number x.sub.0 of a single expiration and inhalation process increases by 2 times or more compared with an average airflow rate zero-crossing number x.sub.a0 in the passing month, determining that a defect of moisture impurities in a breathing tube exists; S5: calculating a comprehensive evaluation coefficient for defect detection of the oil conservator, to obtain defect severity; S6: when the defect severity is a general defect or a severe defect, sending, by the edge intelligent gateway, an evaluation result and corresponding data to an oil conservator defect monitoring cloud platform; and S7: sending, by the oil conservator defect monitoring cloud platform, an alarm command to a client terminal, such that the transformer operation and maintenance personnel access the oil conservator defect monitoring cloud platform through the client terminal to check specific information.

9. The defect detection method for a transformer oil conservator based on edge computing according to claim 8, wherein a formula for calculating the actual oil level height D.sub.1 in step S2 is as follows:
D.sub.1=H−d−h wherein H is a height from the bottom to the top of the interior of the oil conservator, d is a distance from a transmitting end of a microwave transmitting antenna to an oil level, and h is a distance from the transmitting end of the microwave transmitting antenna to the top of the interior of the oil conservator; $d = \sqrt{\frac{P_{t} G_{t} G_{r} λ^{2}}{4 π^{2} P_{r}} - \frac{1}{4} S^{2}}$ wherein S is a distance from the transmitting end of the microwave transmitting antenna to a receiving end of a microwave receiving antenna, λ is a wavelength, P.sub.t is a microwave transmitting power of the microwave transmitting antenna, G.sub.t is a gain of the microwave transmitting antenna, P.sub.r is a detected power of the microwave receiving antenna, and G.sub.r is a gain of the microwave receiving antenna.

10. The defect detection method for a transformer oil conservator based on edge computing according to claim 8, wherein a formula for calculating the comprehensive evaluation coefficient c.sub.k for defect detection of the oil conservator is as follows: $c_{k} = 1.2 p_{k}^{2} + 0.4 d_{k}^{\frac{1}{3}} + 0.7 x_{k}^{\frac{2}{3}} + 1.5 j_{k}^{\frac{2}{3}} + 0.2 s_{k}^{1.2}$ wherein when a capsule damage defect exists, a characteristic value p.sub.k is 2; otherwise, p.sub.k is 1; when a defect of partial blockage of the breathing circuit exists, a characteristic value d.sub.k is 2; otherwise, d.sub.k is 1; when a defect of leakage in the breathing circuit exists, a characteristic value x.sub.k is 2; otherwise, x.sub.k is 1; when a defect of moisture impurities in a breathing tube exists, a characteristic value s.sub.k is 2; otherwise, s.sub.k is 1; when a defect of false oil level of the oil conservator exists, a characteristic value j.sub.k is 2; otherwise, j.sub.k is 1; and the defect severity is determined according to a value of the comprehensive evaluation coefficient c.sub.k for defect detection of the oil conservator: when c.sub.k=4, the defect severity is no defect; when 4<c.sub.k≤4.8, the defect severity is the general defect; and when c.sub.k>4.8, the defect severity is the severe defect.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present disclosure is described in detail below with reference to the accompanying drawings.

[0047] FIG. 1 is a structural diagram of the present disclosure.

[0048] FIG. 2 is a schematic diagram of installation of a sensing terminal according to the present disclosure.

[0049] FIG. 3 is a diagram of an airflow rate curve when a capsule damage defect occurs according to the present disclosure.

[0050] FIG. 4 is a diagram of an airflow rate curve when a defect of partial blockage of a breathing circuit occurs according to the present disclosure.

[0051] FIG. 5 is a diagram of an airflow rate curve when a defect of leakage in a breathing circuit occurs according to the present disclosure.

[0052] FIG. 6 is a diagram of an airflow rate curve when a defect of moisture impurities in a breathing tube occurs according to the present disclosure.

[0053] FIG. 7 is a schematic diagram of a microwave oil level measurement assembly according to the present disclosure.

[0054] In the drawings: 1 is an oil conservator, 2 is a capsule, 3 is a breathing tube, 4 is a dehydrating breather, 5 is an airflow sensor, 6 is an oil temperature sensor, 7 is an ambient temperature sensor, 8 is an oil level gauge, 9 is a microwave transmitting antenna, and 10 is a microwave receiving antenna.

DETAILED DESCRIPTION

[0055] The present disclosure will be further described below in conjunction with specific embodiments.

[0056] As shown in FIG. 1 and FIG. 2, a defect monitoring apparatus for a transformer oil conservator based on edge computing includes: a sensing terminal, an edge intelligent gateway, a monitoring terminal, an oil conservator defect monitoring cloud platform, and a client terminal. The edge intelligent gateway and the monitoring terminal are both disposed in a substation. The monitoring terminal is configured to access the edge intelligent gateway. The sensing terminal includes: an airflow sensor 5, an oil temperature sensor 6, an ambient temperature sensor 7, and a microwave oil level measurement assembly. The airflow sensor 5 is disposed on a breathing tube 3, and is configured to measure a breathing airflow rate of an oil conservator 1. The oil temperature sensor 6 is disposed at a lower portion of a side of the oil conservator 1, and a probe of the oil temperature sensor 6 extends into the oil conservator 1 and is immersed in transformer oil. The oil temperature sensor 6 is configured to measure an oil temperature of the oil conservator. The ambient temperature sensor 7 is disposed outside the oil conservator 1. The ambient temperature sensor 7 is configured to measure an ambient temperature. The microwave oil level measurement assembly is disposed at a top of an inner wall of the oil conservator 1, and the microwave oil level measurement assembly is away from a capsule 2. The microwave oil level measurement assembly is configured to measure a height of an oil level of the oil conservator.

[0057] The sensing terminal sends detection data to the edge intelligent gateway, and an original oil level gauge 8 of the oil conservator also sends data information thereof to the edge intelligent gateway. The edge intelligent gateway stores and evaluates the detection data. The edge intelligent gateway sends an evaluation result indicating a defect and corresponding data to the oil conservator defect monitoring cloud platform. The oil conservator defect monitoring cloud platform sends an alarm command to the client terminal.

[0058] The microwave oil level measurement assembly includes: a microwave transmitting antenna 9 and a microwave receiving antenna 10, where the microwave transmitting antenna 9 and the microwave receiving antenna 10 are both oriented towards the oil face, upper ends of the microwave transmitting antenna 9 and the microwave receiving antenna 10 are both fastened at the top of the inner wall of the oil conservator 1, and a transmitting end of the microwave transmitting antenna 9 is located in a same horizontal plane with a receiving end of the microwave receiving antenna 10.

[0059] The sensing terminal communicates with the edge intelligent gateway through a ZigBee network; the edge intelligent gateway communicates with the monitoring terminal through the ZigBee network, and the edge intelligent gateway communicates with the oil conservator defect monitoring cloud platform through a GPRS network.

[0060] The airflow sensor 5 is disposed close to a dehydrating breather 4.

[0061] The airflow sensor 5 adopts bidirectional airflow rate measurement, with a measurement range of −200 slpm to +200 slpm, a total error band less than or equal to 3% of a reading, and a response time less than or equal to 1 ms.

[0062] The oil temperature sensor 6 and the ambient temperature sensor 7 are both platinum resistance sensors, with a measurement range of −40° C. to 120° C. and accuracy of ±0.5° C.

[0063] The edge intelligent gateway adopts an ARM Cortex-A7 processor, with 1 GB RAM and 8 GB eMMC.

[0064] The client terminal may be a personal computer (PC), a tablet computer, or a smart phone, and supports an email prompt alarm of the PC and the tablet computer, and a short message prompt alarm of the smart phone.

[0065] A defect detection method for a transformer oil conservator based on edge computing includes the following steps:

[0066] S1: A sensing terminal monitors the following data in real time: a breathing airflow rate of an oil conservator, an oil temperature of the oil conservator, an ambient temperature, a microwave transmitting power, and a microwave receiving power.

[0067] S2: Determine whether the oil conservator has a false oil level defect: calculate an actual oil level height D.sub.1 according to the microwave transmitting power and the microwave receiving power; an original oil level gauge of the oil conservator sends data information to an edge intelligent gateway; the edge intelligent gateway calculates a difference between the actual oil level height D.sub.1 and a display value D of the original oil level gauge 8 of the oil conservator; and when the difference is greater than 3 cm, determine that the oil conservator has a false oil level defect; otherwise, determine that the oil conservator has no false oil level defect.

[0068] S3: Sample real-time monitoring data, to form a breathing airflow rate curve; when a change in the ambient temperature is within 10° C. and a change in the oil temperature of the oil conservator is within 4° C., compare a peak breathing airflow rate V.sub.m of the oil conservator monitored in real time with an average peak breathing airflow rate V.sub.a of the oil conservator in the passing month under the same condition; if a difference is greater than or equal to 15%, perform step S4; otherwise, determine that the following four types of defects do not exist: capsule damage, partial blockage of a breathing circuit, leakage in the breathing circuit, or moisture impurities in a breathing tube.

[0069] S4: As shown in FIG. 3, when V.sub.m≥1.2V.sub.a, t.sub.h≤0.9t.sub.ha, and t.sub.x≤0.9t.sub.xa, determine that a capsule damage defect exists.

[0070] where t.sub.h is a single expiration duration monitored in real time, t.sub.x is a single inhalation duration monitored in real time, t.sub.ha is an average single expiration duration in the passing month, and t.sub.xa is an average single inhalation duration in the passing month;

[0071] as shown in FIG. 4, when V.sub.m≤0.8V.sub.a, t.sub.h≥1.1t.sub.ha, and t.sub.x≥1.1t.sub.xa, determine that a defect of partial blockage of the breathing circuit exists;

[0072] as shown in FIG. 5, when V.sub.m≤0.8V.sub.a, |t.sub.h−t.sub.ha|<0.05t.sub.ha, and |t.sub.x−t.sub.xa|<0.05t.sub.xa, determine that a defect of leakage in the breathing circuit exists; and

[0073] as shown in FIG. 6, when V.sub.m≤0.85V.sub.a and an airflow rate zero-crossing number x.sub.0 of a single expiration and inhalation process increases by 2 times or more compared with an average airflow rate zero-crossing number x.sub.a0 in the passing month, determine that a defect of moisture impurities in a breathing tube exists.

[0074] S5: Calculate a comprehensive evaluation coefficient for defect detection of the oil conservator, to obtain defect severity.

[0075] S6: When the defect severity is a general defect or a severe defect, the edge intelligent gateway sends an evaluation result and corresponding data to an oil conservator defect monitoring cloud platform.

[0076] S7: The oil conservator defect monitoring cloud platform sends an alarm command to a client terminal, such that staff access the oil conservator defect monitoring cloud platform through the client terminal to check specific information.

[0077] A formula for calculating the actual oil level height D.sub.1 in step S2 is as follows:

D.sub.1=H−d−h

[0078] where H is a height from the bottom to the top of the interior of an oil conservator, d is a distance from a transmitting end of a microwave transmitting antenna to an oil level, and h is a distance from the transmitting end of the microwave transmitting antenna to the top of the interior of the oil conservator;

[00003] $d = \sqrt{\frac{P_{t} G_{t} G_{r} λ^{2}}{4 π^{2} P_{r}} - \frac{1}{4} S^{2}}$

[0079] As shown in FIG. 7, S is a distance from the transmitting end of the microwave transmitting antenna to a receiving end of a microwave receiving antenna, λ is a wavelength, P.sub.t is a microwave transmitting power of the microwave transmitting antenna, G.sub.t is a gain of the microwave transmitting antenna, P.sub.r is a detected power of the microwave receiving antenna, and G.sub.r is a gain of the microwave receiving antenna.

[0080] A formula for calculating the comprehensive evaluation coefficient c.sub.k for defect detection of the oil conservator is as follows:

[00004] $c_{k} = 1.2 p_{k}^{2} + 0.4 d_{k}^{\frac{1}{3}} + 0.7 x_{k}^{\frac{2}{3}} + 1.5 j_{k}^{\frac{2}{3}} + 0.2 s_{k}^{1.2}$

[0081] where when a capsule damage defect exists, a characteristic value p.sub.k is 2; otherwise, p.sub.k is 1;

[0082] when a defect of partial blockage of the breathing circuit exists, a characteristic value d.sub.k is 2; otherwise, d.sub.k is 1;

[0083] when a defect of leakage in the breathing circuit exists, a characteristic value x.sub.k is 2; otherwise, x.sub.k is 1;

[0084] when a defect of moisture impurities in a breathing tube exists, a characteristic value s.sub.k is 2; otherwise, s.sub.k is 1;

[0085] when a defect of false oil level of the oil conservator exists, a characteristic value j.sub.k is 2; otherwise, j.sub.k is 1; and

[0086] the defect severity is determined according to a value of the comprehensive evaluation coefficient c.sub.k for defect detection of the oil conservator:

[0087] when c.sub.k=4, the defect severity is no defect;

[0088] when 4<c.sub.k≤4.8, the defect severity is the general defect; and

[0089] when c.sub.k>4.8, the defect severity is the severe defect.

[0090] The above embodiments are merely intended to exemplarily illustrate the principles and effects of the present disclosure, rather than to limit the present disclosure. Any person skilled in the art can make modifications or alterations to the foregoing embodiments without departing from the spirit and scope of the present disclosure. Hence, all equivalent modifications or alterations made by those of ordinary skill in the art without departing from the spirit and technical teachings disclosed in the present disclosure shall fall within the scope defined by appended claims to the present disclosure.

DEFECT MONITORING APPARATUS AND DETECTION METHOD FOR TRANSFORMER OIL CONSERVATOR BASED ON EDGE COMPUTING

Inventors

Cpc classification

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H01F2027/406

ELECTRICITY

Classification Explorer

H04W88/16

ELECTRICITY

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G01D21/02

PHYSICS

Classification Explorer

H01F27/14

ELECTRICITY

Classification Explorer

G01K7/26

PHYSICS

Classification Explorer

H04W4/38

ELECTRICITY

Classification Explorer

H01F27/402

ELECTRICITY

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G01K13/00

PHYSICS

International classification

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G01D21/02

PHYSICS

Classification Explorer

H01F27/14

ELECTRICITY

Classification Explorer

G01K7/26

PHYSICS

Abstract

Claims

Description