CN113495228A - Power transformer fault on-line monitoring device and monitoring method thereof - Google Patents

Power transformer fault on-line monitoring device and monitoring method thereof Download PDF

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Publication number
CN113495228A
CN113495228A CN202110932087.6A CN202110932087A CN113495228A CN 113495228 A CN113495228 A CN 113495228A CN 202110932087 A CN202110932087 A CN 202110932087A CN 113495228 A CN113495228 A CN 113495228A
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gas
monitoring
monitoring device
oil
liquid level
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唐剑
汪晓华
王学武
胡尚志
刘东全
盛罗
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Chengdu Jiaxin Electrical Engineering Technology Co Ltd
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Chengdu Jiaxin Electrical Engineering Technology Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/62—Testing of transformers

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Abstract

The invention discloses a power transformer fault on-line monitoring device, which comprises a container communicated with an oil tank of a power transformer body, and also comprises a pressure monitoring device and/or a liquid level monitoring device and/or an imaging device which are electrically connected with a data processing device; the pressure monitoring device is used for monitoring the gas pressure in the container; the liquid level monitoring device is used for monitoring the oil level in the container; the imaging device is used for monitoring an external oil level scale image of the container, and the external oil level scale of the container is used for displaying the oil level inside the container. The invention can monitor and collect the gas production process including gas production rate and gas production rate when the power transformer fails; the online monitoring of the fault accumulated gas production can be realized, and the online monitoring system has higher sensitivity than light gas, lower cost than oil chromatography monitoring and higher accuracy than partial discharge monitoring.

Description

Power transformer fault on-line monitoring device and monitoring method thereof
Technical Field
The invention relates to the technical field of power transmission and distribution, in particular to a power transformer fault online monitoring device.
Background
The power transformer is a key power element of a power system, particularly a large power transformer installed at a system junction position, and has high voltage level, large capacity, complex structure and high manufacturing cost, so that once a fault occurs, the power supply reliability and the operation stability of the power system are seriously affected, and huge economic loss is caused by damage caused by the fault, so that the operation safety of the power transformer is an important prerequisite for the stable safety of the power system and the stable increase of national economy.
Faults of the power transformer body comprise winding faults, sleeve faults, iron core faults and the like, and insulation problems can be induced after the faults occur, so that partial discharge is generated. Under the combined action of fault arc heating and ionization, a large amount of insulating oil near a fault point is vaporized and decomposed to form gas with a certain volume, and the gas density is lower than that of the oil, so that the decomposed gas can be dissolved and ascended simultaneously.
In order to monitor the severity of gas production and give an alarm or trip in time, gas relays are installed on the oil-immersed transformers of 110kV or above. The gas relay (also called gas relay) is a commonly used protector for transformer, it is installed in the pipeline between the oil storage cabinet and the oil tank of the transformer, when the oil is decomposed to produce gas or the oil flow surges due to the internal fault of the transformer, the contact of the gas relay is actuated to connect the appointed control loop, and send out signal alarm (light gas 150mL) or start the protective element to automatically cut off the transformer (heavy gas 2 m/s).
The light gas protection mainly aims at the situations of internal discharge of a transformer, multipoint earthing of an iron core, internal overheating, air entering the same tank and the like, and the principle is that oil in an oil tank is decomposed and vaporized when an internal fault is slight or at the initial stage of the fault, a small amount of gas is generated and accumulated at the top of a gas relay, and when the gas amount exceeds a setting value, an alarm signal is sent out to prompt maintenance personnel to check so as to prevent the development of the fault. The heavy gas protection mainly aims at the scenes of serious turn-to-turn short circuit, ground short circuit and the like, and the principle is that the oil flow speed and the oil level height in a transformer can be changed violently when a serious fault occurs, so that the heavy gas protection action is caused.
Besides the protection of the gas relay, the protection or on-line monitoring technology of the transformer also comprises the differential protection of the transformer, the on-line monitoring of oil chromatography, the partial discharge monitoring and the like. However, the current online monitoring technology can only monitor the fault result, cannot monitor the fault development process, cannot realize the continuous monitoring of the transformer fault, and often the transformer has a development process from the defect to the fault, and the gas production is the most direct expression means. In addition, the oil chromatogram on-line monitoring has high cost, long analysis time and low popularization rate, and the partial discharge monitoring technology is very easy to be interfered and has low reliability.
Disclosure of Invention
In order to solve the problems, the invention provides an on-line monitoring device for a gas production process of a power transformer and a fault early warning method for the power transformer, which can realize on-line monitoring of fault accumulated gas production, have higher sensitivity than light gas, lower cost than oil chromatography monitoring and higher accuracy than partial discharge monitoring.
In order to achieve the purpose, the invention is realized by adopting the following technical scheme:
the invention discloses a power transformer fault on-line monitoring device, which comprises a container communicated with an oil tank of a power transformer body, and also comprises a pressure monitoring device and/or a liquid level monitoring device and/or an imaging device which are electrically connected with a data processing device;
the pressure monitoring device is used for monitoring the pressure inside the container;
the liquid level monitoring device is used for monitoring the oil level in the container;
the imaging device is used for monitoring an external oil level scale image of the container, and the external oil level scale of the container is used for displaying the oil level inside the container.
Further, the invention also comprises a temperature acquisition device which is used for monitoring the internal temperature of the container.
Furthermore, the invention also comprises an early warning device which is connected with the data processing device.
Preferably, the container is a gas relay, the gas relay is arranged on a connecting pipeline between the oil tank of the power transformer body and the oil conservator, and the position of the gas relay is higher than that of the oil tank of the power transformer body.
Preferably, the pressure monitoring device includes: the export of gas relay oil discharge opening communicates the entry of first three-way valve, the first exit linkage pressure transmitter of first three-way valve, the second export of first three-way valve set up end cap or oil storage box, the export of gas relay's gas vent communicates the entry of second three-way valve, the first export of second three-way valve communicates pressure transmitter, and the second export of second three-way valve communicates gas collection box or disposes the end cap, pressure transmitter is connected with the data processing device electricity.
Preferably, the imaging device is a CCD imaging device, and the CCD imaging device is connected to the data processing device through a switch.
As another preferred, the liquid level monitoring device comprises a liquid level sensor, the liquid level sensor is positioned inside the container, and the liquid level sensor is electrically connected with the data processing device.
Preferably, the data processing device comprises a real-time gas content calculation module, and further 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.
The invention also discloses a monitoring method suitable for the power transformer fault on-line monitoring device, which comprises a gas collection amount monitoring method based on the pressure monitoring device and/or a gas collection amount monitoring method based on the CCD imaging device and/or a gas collection amount monitoring method based on the liquid level sensor;
the monitoring method of the gas collection amount based on the pressure monitoring device comprises the following steps:
the real-time measurement pressure value of the differential pressure transmitter is as follows:
p＝ρgh2-(ρg(h1+h0-hqi (Qi))-pQi (Qi)
In the formula, h0Height of gas relay, h1Is the vertical height h of the pressure monitoring device from the oil outlet of the gas relay2For the vertical height h of the pressure monitoring device from the gas relay air release valveQi (Qi)Is the gas height, ρ is the density of the oil, g is the acceleration of gravity, pQi (Qi)Is the gas pressure;
and also
VQi (Qi)＝S*hQi (Qi)
In the formula, VQi (Qi)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;
the method comprises the following steps:
a1, recording the pressure value of the differential pressure transmitter when the gas relay is put into operation as p0, at the moment, hQi (Qi)＝0，VQi (Qi)＝0，pQi (Qi)When the value is equal to 0, then
p0＝ρgh2-(ρg(h1+h0-hQi (Qi))-pQi (Qi)＝ρg(h2-h1-h0)
a2, setting the pressure value, gas height, volume and gas pressure of the differential pressure transmitter as time-varying values respectively as p (t) and hQi (Qi)(t)、VQi (Qi)(t) and pQi (Qi)(t) then
p(t)＝ρgh2-(ρg(h1+h0-hQi (Qi)(t))-pQi (Qi)(t)＝p0+(ρghQi (Qi)(t)-pQi (Qi)(t))
a3, Δ p (t) ═ ρ ghQi (Qi)(t)-pQi (Qi)(t)
Due to the fact that
Figure BDA0003211282590000041
Therefore, the temperature of the molten metal is controlled,
Δp(t)≤ρghqi (Qi)(t)
Then the process of the first step is carried out,
Δp(t)＝p(t)-p0≤ρghqi (Qi)(t)
Figure BDA0003211282590000051
a4, when only pressure monitoring device is available, take
Figure BDA0003211282590000052
As a reference value for the gas level in the gas relay
Figure BDA0003211282590000053
a5, calculating gas collection quantity by combining the sectional area of the gas relay
Figure BDA0003211282590000054
a5, calculating gas collection rate
Figure BDA0003211282590000055
The monitoring method of the gas collection amount based on the CCD imaging device comprises the following steps:
b1, the data processing device acquires an oil level scale image of the observation bin;
b2, carrying out image binarization processing on the oil level scale image, and extracting scale marks;
b3, calculating the liquid level height hOil(t)；
b4, calculating the height h of the gasQi (Qi)(t)；
hQi (Qi)(t)＝h0-hOil(t)
Wherein h is0Height of gas relay, hOil(t) is the real-time oil level height of the gas relay, hQi (Qi)The real-time gas height in the gas relay is obtained;
b5, calculating the gas collection amount by combining the sectional area of the gas relay;
Vqi (Qi)(t)＝S*hQi (Qi)(t)
b6, calculating the gas collection rate;
Figure BDA0003211282590000056
the monitoring method of the gas collection amount based on the liquid level sensor comprises the following steps:
one end of the liquid level sensor is connected with one end of the divider resistor R2 and the input end of the A/D conversion unit, and the other end of the liquid level sensor is connected with the voltage source VccThe other end of the divider resistor R2 is connected with a signal ground; the data processing device obtains the voltage value V at the two ends of the liquid level sensor through the output end of the A/D conversion unit1(t) the resistance value of the liquid level sensor is R1(t)，R1Maximum value R of (t)maxCorresponding to the full oil level height h of the gas relay0，R1(t) minimum value corresponds to the lowest position of the gas relay, i.e. 0, gas height hQi (Qi)(t) the calculation method is as follows:
c1, calculating the resistance value of the liquid level sensor, because
Figure BDA0003211282590000061
Then
Figure BDA0003211282590000062
c2, calculating the liquid level height hOil(t)
Figure BDA0003211282590000063
Then
Figure BDA0003211282590000064
c3, calculating the height h of the gasQi (Qi)(t)
Figure BDA0003211282590000065
c4 calculating gas collection quantity by combining sectional area of gas relay
Figure BDA0003211282590000066
c5 calculating gas collection rate
Figure BDA0003211282590000067
The monitoring method of the gas collection amount based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device comprises the following steps:
a1 obtaining h by liquid level sensor or CCD imaging deviceQi (Qi)(t) and VQi (Qi)(t)
B1, obtaining Δ p (t) ═ p (t) — p by the pressure monitoring device0＝ρghQi (Qi)(t)-pQi (Qi)(t)
C1, from A1, B1, pQi (Qi)(t)＝p(t)-p0-ρghQi (Qi)(t)
D1 obtaining the number of gas molecules from the thermodynamic agenda
Figure BDA0003211282590000071
Wherein R is the gas constant and T (t) is the temperature.
F1, further obtaining the gas production rate
Figure BDA0003211282590000074
Further, the monitoring method further comprises an early warning method, and the early warning method comprises the following early warning modes:
gas production alarm, when Δ p (t) is greater than a first predetermined value and/or hQi (Qi)(t) is greater than a second predetermined value and or VQi (Qi)Greater than a third predetermined value and/or vQi (Qi)When the value is larger than the fourth preset value, an alarm is sent out;
gas production rate alarm when
Figure BDA0003211282590000073
And when the value is larger than the fifth preset value, giving an alarm.
The beneficial effects disclosed by the invention are as follows:
1. the invention can realize the result monitoring and the process monitoring of the power transformer body; the result monitoring expresses whether the fault of the transformer body develops to a certain severity degree, and if so, a monitoring alarm is given; the process monitoring expresses the development process of the fault of the transformer body from weak to serious.
2. The invention can monitor and observe and collect the gas production process of the power transformer, including gas production rate, gas production rate and gas production acceleration.
3. The invention can carry out corresponding prompt and alarm and send out corresponding control signals and/or control instructions according to the fault degree of the power transformer.
4. The invention can realize the on-line monitoring of the fault accumulated gas production, has higher sensitivity than light gas, lower cost than oil chromatogram monitoring and higher accuracy than partial discharge monitoring; the specific comparison is shown in table one:
watch 1
Figure BDA0003211282590000081
Figure BDA0003211282590000091
Drawings
FIG. 1 is a schematic structural view of the present invention;
fig. 2 is a schematic view of a pressure monitoring device.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings.
The invention discloses a power transformer fault on-line monitoring device, which comprises a container communicated with an oil tank of a power transformer body, and also comprises a pressure monitoring device and/or a liquid level monitoring device and/or an imaging device which are electrically connected with a data processing device;
the pressure monitoring device is used for monitoring the gas pressure in the container;
the liquid level monitoring device is used for monitoring the oil level in the container;
the imaging device is used for monitoring an external oil level scale image of the container, and the external oil level scale of the container is used for displaying the oil level inside the container.
The data processing device comprises an early warning device.
Example 1
As shown in fig. 1, the container of the present embodiment employs a buchholz relay 4, and the buchholz relay 4 is mounted on the connecting pipeline 2 between the oil tank 1 and the conservator 3 of the power transformer body.
As shown in fig. 2, the pressure monitoring device includes: the export of buchholz relay oil drain 41 communicates the entry of first three-way valve 9, the first export of first three-way valve 9 communicates pressure transmitter 61, the second export of first three-way valve 9 sets up end cap 10, the export of buchholz relay gas vent 42 communicates the entry of second three-way valve 7, the first export of second three-way valve 7 communicates pressure transmitter 6, second three-way valve 7 includes vertical section with pressure transmitter 6's intercommunication pipeline, the second export of second three-way valve 7 communicates gas collection box 8 or disposes the end cap, pressure transmitter 6 is connected with 11 electricity of data processing device.
The monitoring method of the air collection amount based on the pressure monitoring device comprises the following steps:
the real-time measurement pressure value of the differential pressure transmitter is as follows:
p＝ρgh2-(ρg(h1+h0-hqi (Qi))-pQi (Qi)
In the formula, h0Height of gas relay, h1Is the vertical height h of the pressure monitoring device from the oil outlet of the gas relay2For the vertical height h of the pressure monitoring device from the gas relay air release valveQi (Qi)Is the gas height, ρ is the density of the oil, g is the acceleration of gravity, pQi (Qi)Is qiA body pressure;
and also
VQi (Qi)＝S*hQi (Qi)
In the formula, VQi (Qi)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;
the method comprises the following steps:
a1, recording the pressure value of the differential pressure transmitter when the gas relay is put into operation as p0, at the moment, hQi (Qi)＝0，VQi (Qi)＝0，pQi (Qi)When the value is equal to 0, then
p0＝ρgh2-(ρg(h1+h0-hQi (Qi))-pQi (Qi)＝ρg(h2-h1-h0)
a2, setting the pressure value, gas height, volume and gas pressure of the differential pressure transmitter as time-varying values respectively as p (t) and hQi (Qi)(t)、VQi (Qi)(t) and pQi (Qi)(t) then
p(t)＝ρgh2-(ρg(h1+h0-hQi (Qi)(t))-pQi (Qi)(t)＝p0+(ρghQi (Qi)(t)-pQi (Qi)(t))
a3, Δ p (t) ═ ρ ghQi (Qi)(t)-pQi (Qi)(t)
Due to the fact that
Figure BDA0003211282590000111
Therefore, the temperature of the molten metal is controlled,
Δp(t)≤ρghqi (Qi)(t)
Then the process of the first step is carried out,
Δp(t)＝p(t)-p0≤ρghqi (Qi)(t)
Figure BDA0003211282590000112
a4, when only pressure monitor is available, Renwei
Figure BDA0003211282590000113
As a reference value for the gas level in the gas relay
Figure BDA0003211282590000114
a5, calculating gas collection quantity by combining the sectional area of the gas relay
Figure BDA0003211282590000115
a5, calculating gas collection rate
Figure BDA0003211282590000121
The early warning method comprises the following early warning modes:
gas production alarm, when the delta P is larger than a first preset value (can be set on site), an alarm is given;
the gas production accumulated amount is alarmed, and when h' is larger than a second preset value (can be set on site), an alarm is given;
and (4) alarming the gas production rate, wherein when the gas production rate is greater than a third preset value (can be set on site), an alarm is given.
Example 2
In the embodiment, the imaging device is used for monitoring the height of the oil level of the monitoring container, the imaging device is a CCD imaging device 5, and the CCD imaging device 5 is connected with a data processing device 11 through a switch 12.
The monitoring method of the air collection amount based on the CCD imaging device comprises the following steps:
b1, the data processing device acquires an oil level scale image of the observation bin;
b2, carrying out image binarization processing on the oil level scale image, and extracting scale marks;
b3, calculating the liquid level height hOil(t)；
b4, calculating the height h of the gasQi (Qi)(t)；
hQi (Qi)(t)＝h0-hOil(t)
Wherein h0 is the height of the gas relay, hOil(t) is the real-time oil level height of the gas relay, hQi (Qi)The real-time gas height in the gas relay is obtained;
b5, calculating the gas collection amount by combining the sectional area of the gas relay;
Vqi (Qi)(t)＝S*hQi (Qi)(t)
b6, calculating the gas collection rate;
Figure BDA0003211282590000122
a CCD imaging device 5 may be added to embodiment 1.
Example 3
This embodiment adopts the inside oil level of liquid level monitoring device monitoring container, and liquid level monitoring device includes level sensor, level sensor is located inside the container, and level sensor is connected with the data processing device electricity.
The monitoring method of the air collection amount based on the liquid level sensor comprises the following steps:
level sensor connects divider resistance, acquires the sampling value through divider resistance, calculates the liquid level height, combines buchholz relay's sectional area to calculate the gas collection volume, and is specific:
the monitoring method of the air collection amount based on the liquid level sensor comprises the following steps:
one end of the liquid level sensor is connected with one end of the divider resistor R2 and the input end of the A/D conversion unit, and the other end of the liquid level sensor is connected with the voltage source VccThe other end of the divider resistor R2 is connected with a signal ground; the data processing device obtains the voltage value V at the two ends of the liquid level sensor through the output end of the A/D conversion unit1(t) the resistance value of the liquid level sensor is R1(t)，R1Maximum value R of (t)maxCorresponding to the full oil level height h of the gas relay0，R1(t) minimum value corresponds to the lowest position of the gas relay, i.e. 0, gas height hQi (Qi)(t) the calculation method is as follows:
c1, calculating the resistance value of the liquid level sensor, because
Figure BDA0003211282590000131
Then
Figure BDA0003211282590000132
c2, calculating the liquid level height hOil(t)
Figure BDA0003211282590000133
Then
Figure BDA0003211282590000134
c3, calculating the height h of the gasQi (Qi)(t)
Figure BDA0003211282590000135
c4 calculating gas collection quantity by combining sectional area of gas relay
Figure BDA0003211282590000141
c5 calculating gas collection rate
Figure BDA0003211282590000142
The monitoring method of the gas collection amount based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device comprises the following steps:
a1 obtaining h by liquid level sensor or CCD imaging deviceQi (Qi)(t) and VQi (Qi)(t)
B1, obtaining Δ p (t) ═ p (t) — p by the pressure monitoring device0＝ρghQi (Qi)(t)-pQi (Qi)(t)
C1, from A1, B1, pQi (Qi)(t)＝p(t)-p0-ρghQi (Qi)(t)
D1 obtaining the number of gas molecules from the thermodynamic agenda
Figure BDA0003211282590000143
Wherein R is the gas constant and T (t) is the temperature.
E1, further obtaining the gas production rate
Figure BDA0003211282590000144
The liquid level sensor may be added to embodiment 1 or embodiment 2.
The present invention is capable of other embodiments, and various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention.

Claims (10)

1. Power transformer trouble on-line monitoring device, its characterized in that: the device comprises a container communicated with an oil tank of a power transformer body, and also comprises a pressure monitoring device and/or a liquid level monitoring device and/or an imaging device which are electrically connected with a data processing device;
the pressure monitoring device is used for monitoring the pressure inside the container;
the liquid level monitoring device is used for monitoring the oil level in the container;
the imaging device is used for monitoring an external oil level scale image of the container, and the external oil level scale of the container is used for displaying the oil level inside the container.
2. The power transformer fault on-line monitoring device of claim 1, characterized in that: still include temperature acquisition device, temperature acquisition device is used for monitoring the inside temperature of container.
3. The power transformer fault on-line monitoring device of claim 2, characterized in that: the early warning device is connected with the data processing device.
4. A power transformer fault on-line monitoring device according to claim 1, 2 or 3, characterized in that: the container is a gas relay, the gas relay is arranged on a connecting pipeline between the oil tank of the power transformer body and the oil conservator, and the position of the gas relay is higher than that of the oil tank of the power transformer body.
5. The power transformer fault on-line monitoring device of claim 4, characterized in that: the pressure monitoring device includes: the export of gas relay oil discharge opening communicates the entry of first three-way valve, the first exit linkage pressure transmitter of first three-way valve, the second export of first three-way valve set up end cap or oil storage box, the export of gas relay's gas vent communicates the entry of second three-way valve, the first export of second three-way valve communicates pressure transmitter, and the second export of second three-way valve communicates gas collection box or disposes the end cap, pressure transmitter is connected with the data processing device electricity.
6. A power transformer fault on-line monitoring device 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 with the data processing device through a switch.
7. A power transformer fault on-line monitoring device according to claim 1, 2 or 3, characterized in that: the liquid level monitoring device comprises a liquid level sensor, the liquid level sensor is positioned inside the container, and the liquid level sensor is electrically connected with the data processing device.
8. A power transformer fault on-line monitoring device according to claim 1, 2 or 3, characterized in that: the data processing device comprises a real-time gas content calculation module, and further 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.
9. The monitoring method applicable to the on-line power transformer fault monitoring device according to claim 4, wherein the monitoring method comprises the following steps: the monitoring method comprises a gas collection amount monitoring method based on a pressure monitoring device and/or a gas collection amount monitoring method based on a CCD imaging device and/or a gas collection amount monitoring method based on a liquid level sensor;
the monitoring method of the gas collection amount based on the pressure monitoring device comprises the following steps:
the real-time measurement pressure value of the differential pressure transmitter is as follows:
p＝ρgh2-(ρg(h1+h0-hqi (Qi))-pQi (Qi)
In the formula, h0Height of gas relay, h1Is the vertical height h of the pressure monitoring device from the oil outlet of the gas relay2For the vertical height h of the pressure monitoring device from the gas relay air release valveQi (Qi)Is the gas height, ρ is the density of the oil, g is the acceleration of gravity, pQi (Qi)Is the gas pressure;
and also
VQi (Qi)＝S*hQi (Qi)
In the formula, VQi (Qi)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;
the method comprises the following steps:
a1, recording the pressure value of the differential pressure transmitter as p when the gas relay is put into operation0At this time, hQi (Qi)＝0，VQi (Qi)＝0，pQi (Qi)When the value is equal to 0, then
p0＝ρgh2-(ρg(h1+h0-hQi (Qi))-pQi (Qi)＝ρg(h2-h1-h0)
a2, after the gas relay is put into operation, the pressure of the differential pressure transmitterThe force value, the height of the gas, the volume and the gas pressure are all time-varying values and are respectively set as p (t), hQi (Qi)(t)、VQi (Qi)(t) and pQi (Qi)(t) then
p(t)＝ρgh2-(ρg(h1+h0-hQi (Qi)(t))-pQi (Qi)(t)＝p0+(ρghQi (Qi)(t)-pQi (Qi)(t))
a3, Δ p (t) ═ ρ ghQi (Qi)(t)-pQi (Qi)(t)
Due to the fact that
Figure FDA0003211282580000031
Therefore, the temperature of the molten metal is controlled,
Δp(t)≤ρghqi (Qi)(t)
Then the process of the first step is carried out,
Δp(t)＝p(t)-p0≤ρghqi (Qi)(t)
Figure FDA0003211282580000032
a4, when only pressure monitoring device is available, take
Figure FDA0003211282580000033
As a reference value for the gas level in the gas relay
Figure FDA0003211282580000034
a5, calculating gas collection quantity by combining the sectional area of the gas relay
Figure FDA0003211282580000041
a5, calculating gas collection rate
Figure FDA0003211282580000042
The monitoring method of the gas collection amount based on the CCD imaging device comprises the following steps:
b1, the data processing device acquires an oil level scale image of the observation bin;
b2, carrying out image binarization processing on the oil level scale image, and extracting scale marks;
b3, calculating the liquid level height hOil(t)；
b4, calculating the height h of the gasQi (Qi)(t)；
hQi (Qi)(t)＝h0-hOil(t)
Wherein h is0Height of gas relay, hOil(t) is the real-time oil level height of the gas relay, hQi (Qi)The real-time gas height in the gas relay is obtained;
b5, calculating the gas collection amount by combining the sectional area of the gas relay;
Vqi (Qi)(t)＝S*hQi (Qi)(t)
b6, calculating the gas collection rate;
Figure FDA0003211282580000043
the monitoring method of the gas collection amount based on the liquid level sensor comprises the following steps:
one end of the liquid level sensor is connected with one end of the divider resistor R2 and the input end of the A/D conversion unit, and the other end of the liquid level sensor is connected with the voltage source VccThe other end of the divider resistor R2 is connected with a signal ground; the data processing device obtains the voltage value V at the two ends of the liquid level sensor through the output end of the A/D conversion unit1(t) the resistance value of the liquid level sensor is R1(t)，R1Maximum value R of (t)maxCorresponding to the full oil level height h of the gas relay0，R1(t) minimum value corresponds to the lowest position of the gas relay, i.e. 0, gas height hQi (Qi)(t) the calculation method is as follows:
c1, calculating the resistance value of the liquid level sensor, because
Figure FDA0003211282580000051
Then
Figure FDA0003211282580000052
c2, calculating the liquid level height hOil(t)
Figure FDA0003211282580000053
Then
Figure FDA0003211282580000054
c3, calculating the height h of the gasQi (Qi)(t)
Figure FDA0003211282580000055
c4 calculating gas collection quantity by combining sectional area of gas relay
Figure FDA0003211282580000056
c5 calculating gas collection rate
Figure FDA0003211282580000057
The monitoring method of the gas collection amount based on the pressure monitoring device and the liquid level sensor or based on the pressure monitoring device and the CCD imaging device comprises the following steps:
a1 obtaining h by liquid level sensor or CCD imaging deviceQi (Qi)(t) and VQi (Qi)(t)
B1 obtaining Delta from pressure monitoring devicep(t)＝p(t)-p0＝ρghQi (Qi)(t)-pQi (Qi)(t)
C1, from A1, B1, pQi (Qi)(t)＝p(t)-p0-ρghQi (Qi)(t)
D1 obtaining the number of gas molecules from the thermodynamic agenda
Figure FDA0003211282580000061
Wherein R is the gas constant and T (t) is the temperature.
E1, further obtaining the gas production rate
Figure FDA0003211282580000062
10. The monitoring method according to claim 9, wherein: the early warning method comprises the following early warning modes:
gas production alarm, when Δ p (t) is greater than a first predetermined value and/or hQi (Qi)(t) is greater than a second predetermined value and or VQi (Qi)Greater than a third predetermined value and/or vQi (Qi)When the value is larger than the fourth preset value, an alarm is sent out;
gas production rate alarm when
Figure FDA0003211282580000063
And when the value is larger than the fifth preset value, giving an alarm.
CN202110932087.6A 2021-08-13 2021-08-13 Power transformer fault on-line monitoring device and monitoring method thereof Pending CN113495228A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113804371A (en) * 2021-11-17 2021-12-17 南京博路电气有限公司 Distribution transformer monitoring method and terminal
CN114137443A (en) * 2021-11-19 2022-03-04 华北电力大学 Transformer turn-to-turn short circuit detection system and method based on magnetic flux leakage and pressure
CN116165535A (en) * 2023-04-19 2023-05-26 国网山西省电力公司电力科学研究院 Heavy gas misoperation prevention gas relay detection device and intelligent sensing method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113804371A (en) * 2021-11-17 2021-12-17 南京博路电气有限公司 Distribution transformer monitoring method and terminal
CN114137443A (en) * 2021-11-19 2022-03-04 华北电力大学 Transformer turn-to-turn short circuit detection system and method based on magnetic flux leakage and pressure
CN114137443B (en) * 2021-11-19 2022-09-27 华北电力大学 Transformer turn-to-turn short circuit detection system and method based on magnetic flux leakage and pressure
CN116165535A (en) * 2023-04-19 2023-05-26 国网山西省电力公司电力科学研究院 Heavy gas misoperation prevention gas relay detection device and intelligent sensing method thereof
CN116165535B (en) * 2023-04-19 2023-09-08 国网山西省电力公司电力科学研究院 Heavy gas misoperation prevention gas relay detection device and intelligent sensing method thereof

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