Power transformer fault online monitoring device and monitoring method

Abstract

The present invention discloses an online monitoring device for power transformer faults, including a container connected to the oil tank of the power transformer body, and also including a pressure monitoring device and / or a liquid level monitoring device and / or an imaging device electrically connected to a data processing device; the pressure monitoring device is used to monitor the gas pressure inside the container; the liquid level monitoring device is used to monitor the oil level inside the container; the imaging device is used to monitor the external oil level scale image of the container, and the external oil level scale of the container is used to display the oil level inside the container. The present invention can monitor and collect the gas production process when the power transformer fails, including the gas production amount and the gas production rate; it can realize the online monitoring of the cumulative gas production amount of the fault, and has higher sensitivity than light gas, lower cost than oil chromatography monitoring, and higher accuracy than partial discharge monitoring.

Description

Technical Field

[0001] The invention relates to the technical field of power transmission and distribution, and in particular to an online monitoring device for power transformer faults. Background Art

[0002] Power transformers are key power components of the power system, especially large power transformers installed at the hub of the system. Due to their high voltage level, large capacity, complex structure and high cost, once a failure occurs, it will have a serious impact on the power supply reliability and operational stability of the power system, and damage caused by failure is bound to cause huge economic losses. Therefore, the safe operation of power transformers is an important prerequisite for the stability and safety of the power system and even the stable growth of the national economy.

[0003] The faults of the power transformer include winding faults, bushing faults, core faults, etc. After the fault occurs, it will induce insulation problems and produce partial discharge. Under the combined effect of fault arc heating and ionization, a large amount of insulating oil near the fault point vaporizes and decomposes to form a certain volume of gas. Since the density of gas is lower than that of oil, the decomposed gas will dissolve and rise at the same time.

[0004] In order to monitor the severity of gas production and give timely alarm or trip, all oil-immersed transformers of 110kV and above are currently equipped with gas relays. Gas relays (also known as gas relays) are a commonly used protective device for transformers. They are installed in the pipeline between the oil storage cabinet and the oil tank of the transformer. When the internal fault of the transformer causes the oil to decompose and produce gas or causes oil flow surge, the contacts of the gas relay are activated, the designated control circuit is connected, and a signal alarm is issued in time (light gas 150mL) or the protection element is activated to automatically cut off the transformer (heavy gas 2m / s).

[0005] Among them, light gas protection is mainly aimed at scenarios such as internal discharge of the transformer, multi-point grounding of the core, internal overheating, and air entering the same box. Its principle is that when the internal fault is relatively minor or in the early stage of the fault, the oil in the oil tank is decomposed and vaporized, and a small amount of gas accumulates on the top of the gas relay. When the gas volume exceeds the set value, an alarm signal is issued to prompt maintenance personnel to check and prevent the development of the fault. Heavy gas protection is mainly aimed at serious inter-turn short circuits and short circuits to the ground. Its principle is that in the case of serious faults, the oil flow rate and oil level in the transformer will change dramatically, causing the heavy gas protection to operate.

[0006] In addition to gas relay protection, transformer protection or online monitoring technology also includes transformer differential protection, oil chromatography online monitoring, partial discharge monitoring, etc. However, current online monitoring technologies can only monitor the results of faults, but not the development process of faults, and cannot achieve continuous monitoring of transformer faults. Often, there is a development process from defects to faults in transformers, and gas production is the most direct means of expression. In addition, due to the high cost and long analysis time of oil chromatography online monitoring, its popularity is low, and partial discharge monitoring technology is very susceptible to interference and has low credibility. Summary of the invention

[0007] To solve the above problems, the present invention proposes an online monitoring device for the gas production process of a power transformer and a power transformer fault early warning method, which can realize online monitoring of the cumulative gas production of faults, has higher sensitivity than light gas, lower cost than oil chromatography monitoring, and higher accuracy than partial discharge monitoring.

[0008] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0009] The power transformer fault online monitoring device disclosed in the present invention comprises a container connected to the power transformer body oil tank, and also comprises a pressure monitoring device and / or a liquid level monitoring device and / or an imaging device electrically connected to a data processing device;

[0010] The pressure monitoring device is used to monitor the pressure inside the container;

[0011] The liquid level monitoring device is used to monitor the oil level inside the container;

[0012] The imaging device is used to monitor the external oil level scale image of the container, and the external oil level scale of the container is used to display the oil level inside the container.

[0013] Furthermore, the present invention also includes a temperature acquisition device, which is used to monitor the internal temperature of the container.

[0014] Furthermore, the present invention also includes an early warning device, which is connected to the data processing device.

[0015] Preferably, the container is a gas relay, which is installed on the connecting pipeline between the oil tank of the power transformer body and the oil pillow, and the position of the gas relay is higher than the oil tank of the power transformer body.

[0016] Preferably, the pressure monitoring device includes: the outlet of the oil drain port of the gas relay is connected to the inlet of the first three-way valve, the first outlet of the first three-way valve is connected to the pressure transmitter, the second outlet of the first three-way valve is provided with a plug or an oil storage box, the outlet of the exhaust port of the gas relay is connected to the inlet of the second three-way valve, the first outlet of the second three-way valve is connected to the pressure transmitter, the second outlet of the second three-way valve is connected to the air collecting box or is provided with a plug, and the pressure transmitter is electrically connected to the data processing device.

[0017] As a preferred embodiment, the imaging device is a CCD imaging device, and the CCD imaging device is connected to a data processing device via a switch.

[0018] As another preferred embodiment, the liquid level monitoring device comprises a liquid level sensor, the liquid level sensor is located inside the container, and the liquid level sensor is electrically connected to the data processing device.

[0019] Preferably, the data processing device includes a real-time gas content calculation module, and also includes a pressure monitoring device acquisition and storage module and / or a CCD imaging device acquisition and storage module and / or a liquid level monitoring device acquisition and storage module.

[0020] The present invention also discloses a monitoring method applicable to an online monitoring device for power transformer faults, including a monitoring method for gas collection based on a pressure monitoring device and / or a monitoring method for gas collection based on a CCD imaging device and / or a monitoring method for gas collection based on a liquid level sensor;

[0021] The gas collection amount monitoring method based on the pressure monitoring device is as follows:

[0022] The real-time measured pressure value of the differential pressure transmitter is:

[0023] p=ρgh 2 -(ρg(h 1 +h0-h 气 )-p 气

[0024] In the formula, h 0 is the height of the Buchholz relay, h 1 is the vertical height of the pressure monitoring device from the oil drain port of the gas relay, h 2 is the vertical height of the pressure monitoring device from the gas relay vent valve, h 气 is the gas height, ρ is the density of oil, g is the gravitational acceleration, p 气 is the gas pressure;

[0025] again

[0026] V 气 =S*h 气

[0027] Where V 气 is the volume of the gas, n is the molecular mass of the gas, T is the temperature of the gas, and R is the gas constant;

[0028] The following steps are involved:

[0029] a1. Record the pressure value of the differential pressure transmitter when the gas relay is put into operation. 气 =0, V 气 =0, p 气 =0, then

[0030] p 0 = ρgh 2 -(ρg(h 1 +h 0 -h 气 )-p 气 =ρg(h 2 -h 1 -h 0 )

[0031] a2. When the gas relay is put into operation, the pressure value of the differential pressure transmitter, the height, volume and pressure of the gas are all time-varying values, which are set as p(t), h(t) and h(t) respectively. 气 (t), V 气 (t) and p 气 (t), then

[0032] p(t)=ρgh 2 -(ρg(h 1 +h 0 -h 气 (t))-p 气 (t) = p 0 +(ρgh 气 (t)-p 气 (t))

[0033] a3. Let Δp(t) = ρgh 气 (t)-p 气 (t)

[0034] because

[0035]

[0036] therefore,

[0037] Δp(t)≤ρgh 气 (t)

[0038] but,

[0039] Δp(t)=p(t)-p0≤ρgh 气 (t)

[0040]

[0041] a4. When only pressure monitoring device is used, As a reference value for the gas height in the Buchholz relay,

[0042] a5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay

[0043]

[0044] a5. Calculate the gas collection rate

[0045]

[0046] The gas collection amount monitoring method based on the CCD imaging device comprises the following steps:

[0047] b1. The data processing device obtains the oil level scale image of the observation chamber;

[0048] b2. Perform image binarization processing on the oil level scale image and extract the scale line;

[0049] b3. Calculate the liquid level h 油 (t);

[0050] b4. Calculate the gas height h 气 (t);

[0051] h 气 (t) = h 0 -h 油 (t)

[0052] Among them, h 0 is the height of the Buchholz relay, h 油 (t) is the real-time oil level of the gas relay, h 气 It is the real-time gas height inside the Buchholz relay;

[0053] b5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay;

[0054] V 气 (t) = S * h 气 (t)

[0055] b6. Calculate the gas collection rate;

[0056]

[0057] The method for monitoring the gas collection volume based on the liquid level sensor is as follows:

[0058] One end of the liquid level sensor is connected to one end of the voltage divider resistor R2 and the input end of the A / D conversion unit, and the other end of the liquid level sensor is connected to the voltage source V cc , the other end of the voltage divider resistor R2 is connected to the signal ground; the data processing device obtains the voltage value V at both ends of the liquid level sensor through the output end of the A / D conversion unit 1 (t), the resistance of the liquid level sensor is R 1 (t), R 1 The maximum value of (t)R max The full oil level height of the corresponding gas relay is h 0 , R 1 The minimum value of (t) corresponds to the lowest position of the gas relay, i.e. 0, and the gas height h 气 (t) is calculated as follows:

[0059] c1. Calculate the resistance of the liquid level sensor, because but

[0060]

[0061] c2. Calculate the liquid level h 油 (t)

[0062]

[0063] but

[0064]

[0065] c3. Calculate the gas height h 气 (t)

[0066]

[0067] c4. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay

[0068]

[0069] c5. Calculate the gas collection rate

[0070]

[0071] The gas collection amount monitoring method based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device is as follows:

[0072] A1. Get h from liquid level sensor or CCD imaging device 气 (t) and V 气 (t)

[0073] B1. From the pressure monitoring device, we get Δp(t)=p(t)-p 0 = ρgh气 (t)-p 气 (t)

[0074] C1, obtained from A1 and B1, p 气 (t) = p(t) - p 0 -ρgh 气 (t)

[0075] D1. According to the thermodynamics agenda, the number of gas molecules is

[0076]

[0077] Where R is the gas constant and T(t) is the temperature.

[0078] F1. Further obtain the gas production rate

[0079]

[0080] Furthermore, the monitoring method also includes an early warning method, and the early warning method includes the following early warning modes:

[0081] Gas production alarm, when Δp(t) is greater than the first predetermined value and or h 气 (t) is greater than the second predetermined value and / or V 气 When it is greater than the third predetermined value, or v 气 When it is greater than a fourth predetermined value, an alarm is issued;

[0082] Gas production rate alarm, when When it is greater than a fifth predetermined value, an alarm is issued.

[0083] The beneficial effects disclosed by the present invention are as follows:

[0084] 1. The present invention can realize result monitoring and process monitoring of the power transformer body; result monitoring expresses whether the transformer body fault develops to a certain severity, and if so, a monitoring alarm is given; process monitoring expresses the development process of the transformer body fault from weak to severe.

[0085] 2. The present invention can monitor and observe the gas production process of the power transformer, including the gas production volume, gas production rate and gas production acceleration.

[0086] 3. The present invention can provide corresponding prompts, alarms, and send corresponding control signals and / or control instructions according to the degree of the power transformer fault.

[0087] 4. The present invention can realize online monitoring of the cumulative gas production of faults, has higher sensitivity than light gas, lower cost than oil chromatography monitoring, and higher accuracy than partial discharge monitoring; see Table 1 for specific comparison:

[0088] Table 1

[0089]

[0090] BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 It is a structural schematic diagram of the present invention;

[0092] Figure 2 Schematic diagram of the pressure monitoring device. DETAILED DESCRIPTION

[0093] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0094] The present invention discloses an online monitoring device for power transformer faults, comprising a container connected to the oil tank of the power transformer body, and also comprising a pressure monitoring device and / or a liquid level monitoring device and / or an imaging device electrically connected to a data processing device;

[0095] The pressure monitoring device is used to monitor the gas pressure inside the container;

[0096] The level monitoring device is used to monitor the oil level inside the container;

[0097] The imaging device is used to monitor an image of an external oil level scale of a container, wherein the external oil level scale of the container is used to display the oil level inside the container.

[0098] The data processing device includes an early warning device.

[0099] Example 1

[0100] like Figure 1 As shown, the container of this embodiment adopts a gas relay 4, and the gas relay 4 is installed on the connecting pipeline 2 between the oil tank 1 and the oil pillow 3 of the power transformer body.

[0101] like Figure 2 As shown, the pressure monitoring device includes: the outlet of the gas relay oil drain port 41 is connected to the inlet of the first three-way valve 9, the first outlet of the first three-way valve 9 is connected to the pressure transmitter 61, the second outlet of the first three-way valve 9 is provided with a plug 10, the outlet of the gas relay exhaust port 42 is connected to the inlet of the second three-way valve 7, the first outlet of the second three-way valve 7 is connected to the pressure transmitter 6, the connecting pipeline between the second three-way valve 7 and the pressure transmitter 6 includes a vertical section, the second outlet of the second three-way valve 7 is connected to the air collecting box 8 or is provided with a plug, and the pressure transmitter 6 is electrically connected to the data processing device 11.

[0102] The method for monitoring the gas collection volume based on the pressure monitoring device is as follows:

[0103] The real-time measured pressure value of the differential pressure transmitter is:

[0104] p=ρgh 2 -(ρg(h 1 +h 0 -h 气 )-p 气

[0105] In the formula, h 0 is the height of the Buchholz relay, h 1 is the vertical height of the pressure monitoring device from the oil drain port of the gas relay, h 2 is the vertical height of the pressure monitoring device from the gas relay vent valve, h 气 is the gas height, ρ is the density of oil, g is the gravitational acceleration, p 气 is the gas pressure;

[0106] again

[0107] V 气 =S*h 气

[0108] Where V 气 is the volume of the gas, n is the molecular mass of the gas, T is the temperature of the gas, and R is the gas constant;

[0109] The following steps are involved:

[0110] a1. Record the pressure value of the differential pressure transmitter when the gas relay is put into operation. 气 =0, V 气 =0, p 气 =0, then

[0111] p 0 = ρgh 2 -(ρg(h 1 +h 0 -h 气 )-p 气 =ρg(h 2 -h 1 -h 0 )

[0112] a2. When the gas relay is put into operation, the pressure value of the differential pressure transmitter, the height, volume and pressure of the gas are all time-varying values, which are set as p(t), h(t) and h(t) respectively. 气 (t), V 气 (t) and p 气 (t), then

[0113] p(t)=ρgh 2 -(ρg(h 1+h 0 -h 气 (t))-p 气 (t) = p 0 +(ρgh 气 (t)-p 气 (t))

[0114] a3. Let Δp(t) = ρgh 气 (t)-p 气 (t)

[0115] because

[0116]

[0117] therefore,

[0118] Δp(t)≤ρgh 气 (t)

[0119] but,

[0120] Δp(t)=p(t)-p 0 ≤ρgh 气 (t)

[0121]

[0122] a4. When there is only a pressure monitoring device, As a reference value for the gas height in the Buchholz relay,

[0123] a5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay

[0124]

[0125] a5. Calculate the gas collection rate

[0126]

[0127] The early warning methods include the following:

[0128] Gas production alarm: when ΔP is greater than the first preset value (which can be set on site), an alarm is issued;

[0129] Gas production cumulative alarm: when h' is greater than the second preset value (which can be set on site), an alarm is issued;

[0130] Gas production rate alarm, gas production rate v=dh' / dt, when the gas production rate is greater than a third predetermined value (which can be set on site), an alarm is issued.

[0131] Example 2

[0132] In this embodiment, an imaging device is used to monitor the oil level of the monitoring container. The imaging device is a CCD imaging device 5 . The CCD imaging device 5 is connected to a data processing device 11 via a switch 12 .

[0133] The method for monitoring the gas collection amount based on the CCD imaging device comprises the following steps:

[0134] b1. The data processing device obtains the oil level scale image of the observation chamber;

[0135] b2. Perform image binarization processing on the oil level scale image and extract the scale line;

[0136] b3. Calculate the liquid level h 油 (t);

[0137] b4. Calculate the gas height h 气 (t);

[0138] h 气 (t) = h 0 -h 油 (t)

[0139] Where, h0 is the height of the Buchholz relay, h 油 (t) is the real-time oil level of the gas relay, h 气 It is the real-time gas height inside the Buchholz relay;

[0140] b5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay;

[0141] V 气 (t) = S * h 气 (t)

[0142] b6. Calculate the gas collection rate;

[0143]

[0144] A CCD imaging device 5 can be added to the first embodiment.

[0145] Example 3

[0146] This embodiment uses a liquid level monitoring device to monitor the oil level inside the container. The liquid level monitoring device includes a liquid level sensor. The liquid level sensor is located inside the container and is electrically connected to the data processing device.

[0147] The method for monitoring the gas collection volume based on the liquid level sensor is as follows:

[0148] The liquid level sensor is connected to a voltage divider resistor, and the sampling value is obtained through the voltage divider resistor to calculate the liquid level height. The gas collection volume is calculated in combination with the cross-sectional area of ​​the gas relay. Specifically:

[0149] The method for monitoring the gas collection volume based on the liquid level sensor is as follows:

[0150] One end of the liquid level sensor is connected to one end of the voltage divider resistor R2 and the input end of the A / D conversion unit, and the other end of the liquid level sensor is connected to the voltage source V cc , the other end of the voltage divider resistor R2 is connected to the signal ground; the data processing device obtains the voltage value V at both ends of the liquid level sensor through the output end of the A / D conversion unit 1 (t), the resistance of the liquid level sensor is R 1 (t), R 1 The maximum value of (t)R max The full oil level height of the corresponding gas relay is h 0 , R 1 The minimum value of (t) corresponds to the lowest position of the gas relay, i.e. 0, and the gas height h 气 (t) is calculated as follows:

[0151] c1. Calculate the resistance of the liquid level sensor, because but

[0152]

[0153] c2. Calculate the liquid level h 油 (t)

[0154]

[0155] but

[0156]

[0157] c3. Calculate the gas height h 气 (t)

[0158]

[0159] c4. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay

[0160]

[0161] c5. Calculate the gas collection rate

[0162]

[0163] The gas collection amount monitoring method based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device is as follows:

[0164] A1. Get h from liquid level sensor or CCD imaging device 气 (t) and V 气 (t)

[0165] B1. From the pressure monitoring device, we get Δp(t)=p(t)-p 0 = ρgh 气 (t)-p 气 (t)

[0166] C1, obtained from A1 and B1, p 气 (t) = p(t) - p 0 -ρgh 气 (t)

[0167] D1. According to the thermodynamics agenda, the number of gas molecules is

[0168]

[0169] Where R is the gas constant and T(t) is the temperature.

[0170] E1. Further obtain the gas production rate

[0171]

[0172] The liquid level sensor can be added to the first or second embodiment.

[0173] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A monitoring method for an online monitoring device for power transformer faults, characterized in that: The power transformer fault online monitoring device used is as follows: It includes a container connected to the oil tank of the power transformer body, and also includes a pressure monitoring device and / or a liquid level monitoring device and / or an imaging device electrically connected to the data processing device; The pressure monitoring device is used to monitor the pressure inside the container; The liquid level monitoring device is used to monitor the oil level inside the container; The imaging device is used to monitor the image of the external oil level scale of the container, and the external oil level scale of the container is used to display the oil level inside the container; The container is a gas relay, which is installed on the connecting pipeline between the oil tank of the power transformer body and the oil pillow, and the position of the gas relay is higher than the oil tank of the power transformer body; The detection method includes a method for monitoring the amount of gas collected based on a pressure monitoring device and / or a method for monitoring the amount of gas collected based on a CCD imaging device and / or a method for monitoring the amount of gas collected based on a liquid level sensor; The gas collection amount monitoring method based on the pressure monitoring device is as follows: The real-time measured pressure value of the differential pressure transmitter is: In the formula, is the height of the Buchholz relay, is the vertical height of the pressure monitoring device from the oil drain port of the gas relay. It is the vertical height between the pressure monitoring device and the gas relay vent valve. is the gas height, is the density of oil, is the acceleration due to gravity, is the gas pressure; again In the formula, is the volume of the gas, is the molecular mass of the gas, is the temperature of the gas, is the gas constant; The following steps are involved: a1. Record the pressure value of the differential pressure transmitter when the gas relay is put into operation. ,at this time, , , ,but a2. When the gas relay is put into operation, the pressure value of the differential pressure transmitter, the height, volume and pressure of the gas are all time-varying values, which are set as , , and ,but a3. Set because therefore, but, a4. When only pressure monitoring device is used, As a reference value for the gas height in the Buchholz relay, ; a5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay ； a5. Calculate the gas collection rate The gas collection amount monitoring method based on the CCD imaging device comprises the following steps: b1. The data processing device obtains the oil level scale image of the observation chamber; b2. Perform image binarization processing on the oil level scale image and extract the scale line; b3. Calculate the liquid level ; b4. Calculate gas height ; = - in, is the height of the Buchholz relay, It is the real-time oil level of the gas relay. It is the real-time gas height inside the Buchholz relay; b5. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay; b6. Calculate the gas collection rate; The method for monitoring the gas collection volume based on the liquid level sensor is as follows: One end of the liquid level sensor is connected to one end of the voltage divider resistor R2 and the input end of the A / D conversion unit, and the other end of the liquid level sensor is connected to the voltage source The other end of the voltage divider resistor R2 is connected to the signal ground; the data processing device obtains the voltage value at both ends of the liquid level sensor through the output end of the A / D conversion unit The resistance of the liquid level sensor is , The maximum value of The full oil level height of the gas relay is , The minimum value corresponds to the lowest position of the gas relay, which is 0. The gas height The calculation method is as follows: c1. Calculate the resistance of the liquid level sensor, because ,but c2. Calculate the liquid level but c3. Calculate gas height c4. Calculate the gas collection volume based on the cross-sectional area of ​​the gas relay c5. Calculate the gas collection rate ； The gas collection amount monitoring method based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device is as follows: A1. Obtained by liquid level sensor or CCD imaging device and B1. Obtained by pressure monitoring device C1, obtained from A1 and B1, D1. According to the thermodynamics equation, the number of gas molecules is in, is the gas constant, is temperature; E1. Further obtain the gas production rate 。 2. The monitoring method of the online monitoring device for power transformer fault according to claim 1 is characterized in that: The power transformer fault online monitoring device also includes a temperature acquisition device, and the temperature acquisition device is used to monitor the internal temperature of the container.

3. The monitoring method of the online monitoring device for power transformer fault according to claim 2 is characterized in that: The power transformer fault online monitoring device also includes an early warning device, which is connected to the data processing device.

4. The monitoring method of the online monitoring device for power transformer fault according to claim 1, 2 or 3, characterized in that: The pressure monitoring device includes: the outlet of the oil drain port of the gas relay is connected to the inlet of the first three-way valve, the first outlet of the first three-way valve is connected to the pressure transmitter, the second outlet of the first three-way valve is provided with a plug or an oil storage box, the outlet of the exhaust port of the gas relay is connected to the inlet of the second three-way valve, the first outlet of the second three-way valve is connected to the pressure transmitter, the second outlet of the second three-way valve is connected to the air collecting box or is provided with a plug, and the pressure transmitter is electrically connected to the data processing device.

5. The monitoring method of the online monitoring device for power transformer fault according to claim 1, 2 or 3, characterized in that: The imaging device is a CCD imaging device, and the CCD imaging device is connected to a data processing device via a switch.

6. The monitoring method of the online monitoring device for power transformer fault according to claim 1, 2 or 3, characterized in that: The liquid level monitoring device comprises a liquid level sensor, which is located inside the container and is electrically connected to the data processing device.

7. The monitoring method of the online monitoring device for power transformer fault according to claim 1, 2 or 3, characterized in that: The data processing device comprises a real-time gas content calculation module, and also comprises a pressure monitoring device acquisition and storage module and / or a CCD imaging device acquisition and storage module and / or a liquid level monitoring device acquisition and storage module.

8. The monitoring method of the online monitoring device for power transformer fault according to claim 1 is characterized in that: Also included is an early warning method, which includes the following early warning methods: Gas alarm, when When it is greater than the first predetermined value and or is greater than a second predetermined value and or When it is greater than the third predetermined value and or When it is greater than a fourth predetermined value, an alarm is issued; Gas production rate alarm, when When it is greater than a fifth predetermined value, an alarm is issued.

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