CN113125949A - High-voltage circuit breaker insulation monitoring method and system based on electric field - Google Patents
High-voltage circuit breaker insulation monitoring method and system based on electric field Download PDFInfo
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- 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
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
- G01R31/3271—Testing of circuit interrupters, switches or circuit-breakers of high voltage or medium voltage devices
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- G—PHYSICS
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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Abstract
The invention provides an electric field-based high-voltage circuit breaker insulation monitoring method and system. The system comprises: the system comprises electric field monitoring devices, a relay device, a cloud server and client terminals, wherein the number of the electric field monitoring devices is 3, and the electric field monitoring devices are used for respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time and sending monitoring data to the relay device; the relay device is used for sending the monitoring data to a cloud server; and the cloud server is used for analyzing the monitoring data so as to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker, and sending the monitoring data and the evaluation result to the client terminal. The invention not only can make up the defects of the existing detection means, fill the blank of the non-contact on-line monitoring technology of the high-voltage circuit breaker, but also can effectively monitor the running state of the high-voltage circuit breaker in real time, discover latent defects in time and further ensure the safe and stable running of the breaker equipment of the ultra-high voltage transformer substation in the jurisdiction.
Description
Technical Field
The invention relates to an electric field-based high-voltage circuit breaker insulation monitoring method and system, and belongs to the technical field of high voltage and insulation.
Background
As the core equipment of the power grid, the high-voltage circuit breaker bears the work of breaking the normal working current of the power system and quickly cutting off the fault current of the short-circuit fault lamp, and plays the dual roles of control and protection. In the long-term operation process, the high-voltage circuit breaker bears the influence of factors such as severe electromagnetism, heating power, machinery and the like, so that the problems of internal and external insulation degradation, heating ablation of contacts and the like are inevitably caused, and in the serious case, the operation mechanism of the circuit breaker is possibly refused to operate and mistakenly operates, the switch and the porcelain bushing explode, the contacts are badly contacted and heat seriously, and the metal melts to cause accidents such as grounding short circuit or porcelain bottle explosion and the like. Therefore, the state monitoring and fault diagnosis of the high-voltage circuit breaker have important significance on the safe and stable operation of the power grid.
At present, a method for evaluating the state of the high-voltage circuit breaker mainly depends on three means. One of the methods is to periodically carry out preventive tests, including insulation resistance measurement, dielectric loss tangent value measurement, leakage current measurement, SF6 decomposition product detection, current-carrying loop test, vacuum degree test and the like, and the methods have the disadvantages of large workload, fussy field operation, even power failure treatment and incapability of timely finding potential problems. The other method is field electrification detection, which mainly comprises ultraviolet imaging detection and infrared imaging detection, wherein the ultraviolet imaging method mainly aims at abnormal corona discharge outside a sleeve, the infrared imaging method mainly aims at abnormal heating faults of the surface and a joint of a circuit breaker, and the two methods can not detect the problems of internal and external insulation degradation, contact faults and the like.
The third means is to realize the state evaluation of the circuit breaker by an online monitoring and fault diagnosis technology, namely, directly or indirectly acquiring signals by utilizing sensors such as sound, light, heat, electromagnetism, chemistry, vibration and the like, further classifying and processing the acquired signals to obtain corresponding characteristic parameters, finally performing corresponding recognition and decision algorithm to evaluate and judge the running state of the circuit breaker so as to know whether corresponding overhaul and maintenance measures need to be carried out and predict the development trend of the corresponding state. The on-line monitoring and fault diagnosis means of the circuit breaker are indispensable, and the current common methods comprise leakage current on-line monitoring, vibration signal on-line monitoring, temperature on-line monitoring and the like. At present, a monitoring means capable of identifying the insulation state of the circuit breaker mainly relies on leakage current on-line monitoring, and local discharge characteristics are identified based on leakage current amplitude and high-frequency classification through a method of pre-wiring and internally installing a sensor, so that whether the circuit breaker has external insulation degradation or not is judged. The method is common in use, but has certain problems, such as complex installation and wiring, troublesome later maintenance once damaged, large high-frequency interference and low reliability of partial discharge detection results.
Disclosure of Invention
The invention aims to provide an electric field-based high-voltage circuit breaker insulation monitoring method and system, which can accurately monitor the degradation degree of a high-voltage circuit breaker in real time in a non-contact mode, and inform a terminal user in time after an obvious internal insulation fault is identified, so as to remind a transformer substation operation and maintenance worker to carry out operation and maintenance in time.
In order to solve the technical problems, the invention adopts the following technical scheme:
in one aspect, the invention provides an electric field-based insulation monitoring method for a high-voltage circuit breaker, which comprises the following steps:
respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time;
the monitored data is analyzed to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker.
Further, the identification and evaluation of the external insulation degradation condition of the high-voltage circuit breaker specifically comprises:
according to the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker, calculating the change rate of the electric field intensity amplitude compared with two adjacent time periods of the characteristic position of each phase of high-voltage circuit breaker, when the value is stable and basically remains unchanged in a preset time period, completing self-checking, and initializing a clock to be 0;
dividing the total monitoring time into a plurality of same time intervals, and monitoring to obtain the average value of the electric field intensity amplitude of the characteristic position of each phase of high-voltage circuit breaker in each time interval;
according to the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in each time interval, solving the electric field intensity change rate in the adjacent time interval and the electric field intensity change rate in the total time interval of each phase high-voltage circuit breaker characteristic position;
and judging the external insulation degradation condition of the high-voltage circuit breaker based on a set standard according to the electric field strength change rate in the adjacent time interval at the characteristic position of each phase of high-voltage circuit breaker and the electric field strength change rate in the total time interval.
Further, the setting criteria include:
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 10% -20%, the high-voltage circuit breaker of the phase is considered to be likely to have internal slight deterioration;
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 20% -30%, the high-voltage circuit breaker of the phase is considered to have internal moderate degradation;
and if the change rate of the electric field strength in the adjacent time interval is not less than 0, the change rate of the electric field strength amplitude in at least one adjacent time interval is more than 5%, and the change rate of the electric field strength in the total time interval is more than 30%, the phase high-voltage circuit breaker is considered to have serious internal degradation.
Further, when in the k-th period, the corresponding delta at the characteristic position of each phase high-voltage circuit breakerx(k) Greater than 10%, and deltaA(k)、δB(k)、δC(k) When the deviation of the three values from the average value is not more than 8%, the calculation formula of the electric field intensity change rate in the total time interval is as follows:
wherein k is more than 1 and less than or equal to n, n is the total time interval, and deltax(k) Representing the change rate of the electric field intensity amplitude of each phase of high-voltage circuit breaker characteristic position in the kth period compared with the (k-1) th period, wherein x is A, B and C; etax(n) the rate of change of electric field intensity in the overall time interval, Ex(nT) represents the average value of the electric field intensity amplitude of each phase of high-voltage circuit breaker at characteristic position in nth time period, Ex(0) And the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in the first time period is represented.
In another aspect, the present invention provides an electric field-based insulation monitoring system for a high voltage circuit breaker, comprising: an electric field monitoring device, a relay device, a cloud server and a client terminal,
the number of the electric field monitoring devices is 3, and the electric field monitoring devices are used for respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time and sending monitoring data to the relay device;
the relay device is used for sending the monitoring data to a cloud server;
and the cloud server is used for analyzing the monitoring data so as to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker, and sending the monitoring data and the evaluation result to the client terminal.
And furthermore, 3 electric field monitoring devices are respectively installed outside three sleeve flanges of the high-voltage circuit breaker and at installation positions corresponding to each other, or are respectively installed at the shell of the three-phase transmission mechanism of the high-voltage circuit breaker and at installation positions corresponding to each other.
Furthermore, 3 electric field monitoring devices are respectively installed at the position where the gradient change of the electric field intensity outside the three sleeve flanges of the high-voltage circuit breaker is the most severe, or are respectively installed at the position where the gradient change of the electric field intensity of the shell of the three-phase transmission mechanism of the high-voltage circuit breaker is the most severe.
Further, the calculation method of the position where the electric field intensity gradient changes most severely comprises the following steps:
if the electric field monitoring device is installed outside the flange, the calculation is carried out according to the following formula:
Wherein, gradE (x, y, h)0) As a space coordinate of (x, y, h)0) A gradient of the electric field strength E of (d); h is0The height of the installation position of the electric field monitoring device; r islimitAn extreme position suitable for mounting on the outer side of the flange; e (h)0) For electric field monitoring devices mounted at h0The electric field strength of (d);
if the electric field monitoring device is installed outside the transmission mechanism, the calculation is carried out according to the following formula:
Wherein, gradE ' (x ', y ', h)0') is a space coordinate of (x ', y ', h)0') the gradient of the electric field strength E'; h is0' is the height of the installation place of the electric field monitoring device; x is the number oflimitFor extreme positions, y, suitable for mounting in the direction of the x-axis outside the mechanismlimitThe limit position is suitable for installation in the y-axis direction outside the mechanism; e' (h)0') is an electric field monitoring device arranged at h0The electric field strength of (d). Further, the cloud server is configured to perform the following operations:
according to the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker, calculating the change rate of the electric field intensity amplitude compared with two adjacent time periods of the characteristic position of each phase of high-voltage circuit breaker, when the value is stable and basically remains unchanged in a preset time period, completing self-checking, and initializing a clock to be 0;
dividing the total monitoring time into a plurality of same time intervals, and monitoring to obtain the average value of the electric field intensity amplitude of the characteristic position of each phase of high-voltage circuit breaker in each time interval;
according to the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in each time interval, solving the electric field intensity change rate in the adjacent time interval and the electric field intensity change rate in the total time interval of each phase high-voltage circuit breaker characteristic position;
and judging the external insulation degradation condition of the high-voltage circuit breaker based on a set standard according to the electric field strength change rate in the adjacent time interval at the characteristic position of each phase of high-voltage circuit breaker and the electric field strength change rate in the total time interval.
Further, the electric field monitoring device comprises a d-dot electric field probe, an amplifying and filtering module, a first Lora communication module, a first MCU module, a first lithium battery, a first battery voltage acquisition module and a first charging protection module, wherein,
the d-dot electric field probe is used for detecting the power frequency electric field intensity and sending a power frequency electric field signal to the amplifying and filtering module;
the amplifying and filtering module is used for amplifying the power frequency electric field signal, filtering out high-frequency electromagnetic interference components and outputting the high-frequency electromagnetic interference components to an ADC port of the first MCU module;
the first battery voltage acquisition module is used for converting the voltage of the first lithium battery into an ADC (analog to digital converter) signal which can be read by the first MCU module;
the first MCU module is used for collecting a power frequency electric field signal of the ADC port, eliminating external interference and then transmitting the power frequency electric field signal to the first Lora communication module; the battery voltage signal acquisition module is used for acquiring a battery voltage signal of the ADC port and transmitting the battery voltage signal to the first Lora communication module;
the first Lora communication module is used for transmitting the power frequency electric field signal and the battery voltage signal to the relay device;
the first lithium battery supplies power to the amplifying and filtering module, the first Lora communication module and the first MCU module;
the first charging protection module is used for preventing the first lithium battery from being overcharged when the first lithium battery is charged.
Further, the first MCU module is configured to perform the following operations:
collecting a first lithium battery voltage signal, judging the first lithium battery voltage signal, starting a first timer if the battery voltage is greater than 80% of the rated voltage, collecting an electric field signal, performing filtering processing, sending the electric field signal and the voltage signal to a first Lora communication module, further entering a sleep mode, and turning off a peripheral, setting the first timer to 0 after the first timer times for 15 minutes, interrupting the sleep by a first MCU module, turning on the peripheral, and continuously collecting the first lithium battery voltage signal;
if the voltage of the first lithium battery is less than 80% of the rated voltage of the first lithium battery but greater than 70% of the rated voltage of the first lithium battery, starting a second timer, collecting electric field signals, performing filtering processing, sending the electric field signals and voltage signals to a first Lora communication module, further entering a sleep mode, and turning off a peripheral, setting the second timer to 0 after the second timer times for 60 minutes, interrupting the sleep by the first MCU module, turning on the peripheral, and continuously collecting the voltage signals of the first lithium battery;
if the voltage of the first lithium battery is less than 70% of the rated voltage of the first lithium battery, starting a third timer, then entering a sleep mode, closing the peripheral, setting the third timer to 0 after the third timer times for 4 hours, interrupting the sleep by the first MCU module, opening the peripheral, and continuously acquiring the voltage signal of the first lithium battery.
Furthermore, the relay device comprises a second Lora communication module, a GPRS module, a second MCU module, a second lithium battery, a second battery voltage acquisition module and a second charging protection module, wherein the second Lora communication module is configured to receive a signal sent by the electric field monitoring device and transmit the signal to the second MCU module; the second battery voltage acquisition module is used for converting the voltage of the second lithium battery into an ADC (analog to digital converter) signal which can be read by the second MCU module; the second MCU module is used for analyzing the received electric field signals from the three phases, sequentially sending the electric field signals to the GPRS module, then transmitting the electric field signals to the cloud server through the GPRS module, and collecting the battery voltage signals of the ADC port and transmitting the battery voltage signals to the cloud server through the GPRS module; the second lithium battery supplies power to the GPRS module, the second Lora communication module and the second MCU module; the second charging protection module is used for preventing the second lithium battery from being overcharged when the second lithium battery is charged.
The invention achieves the following beneficial technical effects:
according to the invention, the power frequency electric field intensity outside the sleeve flange of the high-voltage circuit breaker or at the shell of the transmission mechanism is monitored in real time in a non-contact manner, so that whether the high-voltage circuit breaker has obvious external insulation deterioration signs such as internal moisture or the like is accurately judged, the purpose of timely acquiring the running state of the high-voltage circuit breaker is achieved, the defects of the existing detection means can be made up, the blank of the non-contact online monitoring technology of the high-voltage circuit breaker is filled, the running state of the high-voltage circuit breaker can be effectively monitored in real time, the latent defect is discovered in time, and the safe and stable running of the ultra.
Drawings
Fig. 1 is a working schematic diagram of an electric field-based insulation monitoring system for a high-voltage circuit breaker according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the operation of the electric field monitoring device;
FIG. 3 is a flowchart of the operation of the first MCU module;
FIG. 4 illustrates an installation of the electric field monitoring device;
FIG. 5 is a schematic diagram of the operation of the relay device;
FIG. 6 is a flow chart of a method for identifying degradation of external insulation of a high-voltage circuit breaker;
wherein, 1 the installation position of electric field monitoring devices outside the flange, 2 the installation position of electric field monitoring devices in the transmission mechanism shell department.
Detailed Description
The invention is further described with reference to specific examples. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The deterioration of the internal and external insulation of the high-voltage circuit breaker generally shows that oil paper insulation is affected with damp, SF6 contains electrolytes such as micro water, switch contacts are damaged, the edge surfaces or sealing parts are affected with damp, and the deterioration phenomena can cause the overall dielectric property and the conductive property of the high-voltage circuit breaker to be changed, so that the spatial electric field distribution of the high-voltage circuit breaker is influenced. In view of the above, the invention provides an electric field-based insulation monitoring method and system for a high-voltage circuit breaker, which are installed outside a bushing flange of the circuit breaker or at a transmission mechanism shell in a magnetic attraction manner, and identify and evaluate the degradation state of the circuit breaker by monitoring the amplitude of a power frequency electric field near the shell of a three-phase operating mechanism.
In one embodiment, the present invention provides an electric field based insulation monitoring method for a high voltage circuit breaker, the method comprising:
respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time;
the monitored data is analyzed to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker.
According to one embodiment, the method for identifying and evaluating the external insulation degradation condition of the high-voltage circuit breaker specifically comprises the following steps:
according to the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker, calculating the change rate of the electric field intensity amplitude compared with two adjacent time periods of the characteristic position of each phase of high-voltage circuit breaker, when the value is stable and basically remains unchanged in a preset time period, completing self-checking, and initializing a clock to be 0;
dividing the total monitoring time into a plurality of same time intervals, and monitoring to obtain the average value of the electric field intensity amplitude of the characteristic position of each phase of high-voltage circuit breaker in each time interval;
according to the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in each time interval, solving the electric field intensity change rate in the adjacent time interval and the electric field intensity change rate in the total time interval of each phase high-voltage circuit breaker characteristic position;
and judging the external insulation degradation condition of the high-voltage circuit breaker based on a set standard according to the electric field strength change rate in the adjacent time interval at the characteristic position of each phase of high-voltage circuit breaker and the electric field strength change rate in the total time interval.
Wherein, the setting criteria include:
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 10% -20%, the high-voltage circuit breaker of the phase is considered to be likely to have internal slight deterioration;
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 20% -30%, the high-voltage circuit breaker of the phase is considered to have internal moderate degradation;
and if the change rate of the electric field strength in the adjacent time interval is not less than 0, the change rate of the electric field strength amplitude in at least one adjacent time interval is more than 5%, and the change rate of the electric field strength in the total time interval is more than 30%, the phase high-voltage circuit breaker is considered to have serious internal degradation.
In another embodiment, as shown in fig. 1, the present invention provides an electric field based insulation monitoring system for a high voltage circuit breaker, comprising: the system comprises an electric field monitoring device, a relay device, a cloud server and a client terminal.
The number of the electric field monitoring devices is 3, the electric field monitoring devices are used for respectively monitoring the power frequency electric field intensity amplitude values at the three-phase characteristic positions of the high-voltage circuit breaker A, B, C in real time, and monitoring data are sent to the relay device.
The relay device is used for sending the monitoring data to a cloud server.
And the cloud server analyzes the monitoring data by utilizing an analysis and identification algorithm carried in the cloud server so as to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker, and sends the monitoring data and an evaluation result to the client terminal.
The client terminal can access the cloud server to acquire the working states of the electric field monitoring device and the relay device, electric field data monitored in real time at the three-phase characteristic position of the high-voltage circuit breaker A, B, C and the identification result of the external insulation degradation condition of the high-voltage circuit breaker.
The electric field monitoring device is adhered to the outside of a sleeve flange of the high-voltage circuit breaker or the shell of the transmission mechanism in a magnetic attraction mode, the installation mode is shown in figure 4, wherein 1 is the installation position of the electric field monitoring device at the outside of the flange, and 2 is the installation position of the electric field monitoring device at the shell of the transmission mechanism. The electric field monitoring device is not directly electrically connected with the high-voltage circuit breaker, so that non-contact on-line monitoring can be realized.
It should be noted that the electric field monitoring devices are three and are respectively arranged at the same position of each phase of the high-voltage circuit breaker.
In a preferred embodiment, the three electric field monitoring devices are respectively installed at the position where the gradient of the electric field intensity outside the sleeve flange of the high-voltage circuit breaker is the most severe, or respectively installed at the position where the gradient of the electric field intensity of the shell of the three-phase transmission mechanism of the high-voltage circuit breaker is the most severe.
The calculation method of the position with the most severe change of the electric field intensity gradient comprises the following steps:
if the electric field monitoring device is installed outside the flange, the calculation is carried out according to the following formula:
Wherein, gradE (x, y, h)0) As a space coordinate of (x, y, h)0) A gradient of the electric field strength E of (d); h is0The height of the installation position of the electric field monitoring device; r islimitAn extreme position suitable for mounting on the outer side of the flange; e (h)0) For electric field monitoring devices mounted at h0The electric field strength of (d);
if the electric field monitoring device is installed outside the transmission mechanism, the calculation is carried out according to the following formula:
Wherein, gradE ' (x ', y ', h)0') is a space coordinate of (x ', y ', h)0') the gradient of the electric field strength E'; h is0' is the height of the installation place of the electric field monitoring device; x is the number oflimitFor extreme positions, y, suitable for mounting in the direction of the x-axis outside the mechanismlimitThe limit position is suitable for installation in the y-axis direction outside the mechanism; e' (h)0') is an electric field monitoring device arranged at h0The electric field strength of (d).
As shown in fig. 2, the electric field monitoring device includes a d-dot electric field probe, an amplifying and filtering module, a first Lora communication module, a first MCU module, a first lithium battery, a first battery voltage collecting module, and a first charging protection module.
The d-dot electric field probe is used for detecting the power frequency electric field intensity and sending a power frequency electric field signal to the amplifying and filtering module;
the amplifying and filtering module is used for amplifying the power frequency electric field signal, filtering out high-frequency electromagnetic interference components and outputting the high-frequency electromagnetic interference components to an ADC port of the first MCU module;
the first battery voltage acquisition module is used for converting the voltage of the first lithium battery into an ADC (analog to digital converter) signal which can be read by the first MCU module;
the first MCU module is used for collecting a power frequency electric field signal of the ADC port, eliminating external interference and then transmitting the power frequency electric field signal to the first Lora communication module; the battery voltage signal acquisition module is used for acquiring a battery voltage signal of the ADC port and transmitting the battery voltage signal to the first Lora communication module;
the first Lora communication module is used for transmitting the power frequency electric field signal and the battery voltage signal to the relay device;
the first lithium battery supplies power to the amplifying and filtering module, the first Lora communication module and the first MCU module;
the first charging protection module is used for preventing the first lithium battery from being overcharged when the first lithium battery is charged.
The working principle of the electric field monitoring device is as follows: the d-dot electric field probe works in a passive state; the amplifying and filtering module amplifies a weak electric field signal input by the d-dot electric field probe, filters a high-frequency electromagnetic interference component and outputs the high-frequency electromagnetic interference component to an ADC port of the first MCU module; the first MCU module collects power frequency electric field signals of an ADC port, external interference is further eliminated in a software filtering mode, and then the signals are transmitted to the first Lora communication module to realize wireless data transmission; the first battery voltage acquisition module converts the voltage of the first lithium battery into an ADC (analog to digital converter) signal which can be read by the first MCU (micro control unit) in a resistance voltage division mode, and the first MCU module acquires a battery voltage signal of a first ADC port and then transmits the battery voltage signal to the first Lora communication module; when the first lithium battery feeds, the first lithium battery is charged through the first charging protection module through the solar cell panel.
In order to ensure 100% online rate and continuous work of the electric field monitoring device, the embodiment of the invention adopts a software low-power consumption method to ensure that the solar cell panel and the first lithium battery can uninterruptedly supply power to the electric field monitoring device. For this purpose, the first MCU module is provided with a first timer, a second timer, and a third timer. As shown in fig. 3, the first MCU module is configured to perform the following operations:
the method comprises the following steps that a first MCU module starts to run, collects voltage signals of a first lithium battery and judges the voltage signals, if the voltage of the battery is greater than 80% of the rated voltage, a first timer is started, electric field signals are collected, the electric field signals and the voltage signals are sent to a first Lora communication module after filtering processing is carried out, then the sleep mode is started, and peripherals are closed (namely all I/O ports of the first MCU module are closed, all program functions are closed, and only a timer interruption function is reserved);
if the voltage of the first lithium battery is less than 80% of the rated voltage of the first lithium battery but greater than 70% of the rated voltage of the first lithium battery, starting a second timer, collecting electric field signals, performing filtering processing, sending the electric field signals and voltage signals to a first Lora communication module, further entering a sleep mode, and turning off a peripheral, setting the second timer to 0 after the second timer times for 60 minutes, interrupting the sleep by the first MCU module, turning on the peripheral, and continuously collecting the voltage signals of the first lithium battery;
if the voltage of the first lithium battery is less than 70% of the rated voltage of the first lithium battery, starting a third timer, then entering a sleep mode, closing the peripheral, setting the third timer to 0 after the third timer times for 4 hours, interrupting the sleep by the first MCU module, opening the peripheral, and continuously acquiring the voltage signal of the first lithium battery.
As shown in fig. 5, the relay device includes a second Lora communication module, a GPRS module, a second MCU module, a second lithium battery, a second battery voltage collecting module, and a second charging protection module.
The second Lora communication module is used for receiving signals sent by the electric field monitoring device and transmitting the signals to the second MCU module; the second battery voltage acquisition module is used for converting the voltage of the second lithium battery into an ADC (analog to digital converter) signal which can be read by the second MCU module; the second MCU module is used for analyzing the received electric field signals from the three phases, sequentially sending the electric field signals to the GPRS module, then transmitting the electric field signals to the cloud server through the GPRS module, and collecting the battery voltage signals of the ADC port and transmitting the battery voltage signals to the cloud server through the GPRS module; the second lithium battery supplies power to the GPRS module, the second Lora communication module and the second MCU module; the second charging protection module is used for preventing the second lithium battery from being overcharged when the second lithium battery is charged.
The cloud server stores and analyzes the received three-phase data, and performs degradation degree identification, wherein the flow of a degradation degree identification algorithm is shown in fig. 6, and specifically comprises the following steps:
(1) the cloud server is started, the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker is received, the change rate of the amplitude of the electric field intensity compared between two adjacent time periods is obtained, when the value is stable and basically remains unchanged within a preset time period t, self-checking is completed, and an initialization clock is 0;
(2) dividing the total monitoring time into n time intervals, and setting the time length of each time interval as T. Monitoring and acquiring the average value E of the electric field intensity amplitude of each phase of high-voltage circuit breaker at the characteristic position in the first time intervalx(0) … … average value E of electric field intensity amplitude in (n-1) th periodx(n-1) T), average value E of electric field intensity amplitude in nth periodx(nT), wherein x ═ a, B, C; then, the change rate of the electric field intensity amplitude of the characteristic position of each phase of the high-voltage circuit breaker in the kth time interval (1 < k is less than or equal to n) and the (k-1) th time interval is obtained, namely the change rate delta of the electric field intensity in the adjacent time intervalx(k) (ii) a Then, the change rate of the electric field intensity amplitude of the characteristic position of each phase of the high-voltage circuit breaker in the nth time interval compared with the first time interval, namely the change rate eta of the electric field intensity in the overall time interval is obtainedx(n) of (a). The calculation formula is shown in formulas (1) and (2):
in the formula, Ex((k-1) T) represents the average value of the electric field intensity amplitude in the (k-1) th time period at the characteristic position of each phase of the high-voltage circuit breaker, Ex(kT) represents an average value of the electric field intensity amplitude in the kth period at the characteristic position of the high-voltage circuit breaker of each phase.
According to the data obtained by the calculation in the step (2), based on the set standard, the external insulation degradation condition of the high-voltage circuit breaker is identified:
if all deltas are obtainedx(k) Are all kept not less than 0, and etax(n) 10% -20%, it is considered that the internal light deterioration of the phase high-voltage circuit breaker may occur; if all deltas are obtainedx(k) Are all kept not less than 0, and etax(n) 20% -30%, the internal moderate degradation of the phase high-voltage circuit breaker is considered to be possible; if all deltas are obtainedx(k) Are all kept not less than 0 and have at least one deltax(k) Greater than 5%, while ηx(n) is greater than 30%, it is considered that the phase high-voltage circuit breaker has internal serious deterioration.
In a preferred embodiment, the pair of high voltage circuit breaker characteristic positions if within the kth time periodDelta ofx(k) Sudden significant changes, close in magnitude to each other, can be assumed to be due to a change in the operating voltage of the high voltage circuit breaker or other environmental factors. At this time, the rate of change η of the electric field intensity within the overall time intervalx(n) needs to be rewritten into the expression form of formula (3) to eliminate the influence of the external environment change on the electric field intensity amplitude, which is specifically as follows:
in the present embodiment, the aforementioned "significant change" means δx(k) Greater than 10%, the foregoing "close in size" means δA(k)、δB(k)、δC(k) The deviation of the three values from their mean value is not more than 8%.
It should be noted that, in the actual working process of the system, the situation that the electric field monitoring data is not sent to the relay device because the battery voltage of the electric field monitoring device is lower than 70% occurs, so that the cloud server cannot receive the real-time electric field numerical value, the cloud server stops the degradation degree identification at the moment so as to avoid misjudgment, and the degradation degree identification is performed after the electric field data is received.
Taking the monitoring situation of the degradation degree of a certain phase of a 220kV oil-less breaker of a certain transformer substation as an example, a light degradation alarm is sent out at 10 am on 13 th of 10 months. In this example, T is taken to be 10 minutes and T is taken to be 1 hour. According to the degradation degree analysis and identification algorithm, the electric field intensity at the characteristic position monitored and obtained during alarming reaches 36.5kV/m and E thereofx(0) Rate of change of electric field intensity η over the total time interval, compared to 32.1kV/mx13.7% or more than 10%, and the rate of change of electric field intensity within the adjacent time interval is deltaxNot less than 0, so a light deterioration alarm is sent out.
According to the embodiment, the power frequency electric field intensity outside the sleeve flange of the high-voltage circuit breaker or at the shell of the transmission mechanism is monitored in real time in a non-contact manner, so that whether the high-voltage circuit breaker has obvious external insulation deterioration signs such as internal moisture and the like is accurately judged, the purpose of timely acquiring the running state of the high-voltage circuit breaker is achieved, the defects of the existing detection means can be overcome, the blank of the non-contact online monitoring technology of the high-voltage circuit breaker is filled, the running state of the high-voltage circuit breaker can be effectively monitored in real time, the latent defect is discovered in time, and the safe and stable running of the ultra-high voltage transformer substation in the jurisdiction is.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The present invention has been disclosed in terms of the preferred embodiment, but is not intended to be limited to the embodiment, and all technical solutions obtained by substituting or converting equivalents thereof fall within the scope of the present invention.
Claims (10)
1. An electric field-based insulation monitoring method for a high-voltage circuit breaker, comprising:
respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time;
the monitored data is analyzed to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker.
2. The method according to claim 1, wherein identifying and evaluating the external insulation degradation of the high voltage circuit breaker comprises:
according to the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker, calculating the change rate of the electric field intensity amplitude compared with two adjacent time periods of the characteristic position of each phase of high-voltage circuit breaker, when the value is stable and basically remains unchanged in a preset time period, completing self-checking, and initializing a clock to be 0;
dividing the total monitoring time into a plurality of same time intervals, and monitoring to obtain the average value of the electric field intensity amplitude of the characteristic position of each phase of high-voltage circuit breaker in each time interval;
according to the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in each time interval, solving the electric field intensity change rate in the adjacent time interval and the electric field intensity change rate in the total time interval of each phase high-voltage circuit breaker characteristic position;
and judging the external insulation degradation condition of the high-voltage circuit breaker based on a set standard according to the electric field strength change rate in the adjacent time interval at the characteristic position of each phase of high-voltage circuit breaker and the electric field strength change rate in the total time interval.
3. The method of claim 2, wherein setting the criteria comprises:
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 10% -20%, the high-voltage circuit breaker of the phase is considered to be likely to have internal slight deterioration;
if the change rate of the electric field strength in the adjacent time interval is not less than 0 and the change rate of the electric field strength in the total time interval reaches 20% -30%, the high-voltage circuit breaker of the phase is considered to have internal moderate degradation;
and if the change rate of the electric field strength in the adjacent time interval is not less than 0, the change rate of the electric field strength amplitude in at least one adjacent time interval is more than 5%, and the change rate of the electric field strength in the total time interval is more than 30%, the phase high-voltage circuit breaker is considered to have serious internal degradation.
4. Method according to claim 2, characterized in that, when in the kth time period, the corresponding δ at each phase high voltage breaker characteristic positionx(k) Greater than 10%, and deltaA(k)、δB(k)、δC(k) When the deviation of the three values from the average value is not more than 8%, the calculation formula of the electric field intensity change rate in the total time interval is as follows:
wherein k is more than 1 and less than or equal to n, n is the total time interval, and deltax(k) Representing the change rate of the electric field intensity amplitude of each phase of high-voltage circuit breaker characteristic position in the kth period compared with the (k-1) th period, wherein x is A, B and C; etax(n) electric field intensity variation in the overall period intervalRate, Ex(nT) represents the average value of the electric field intensity amplitude of each phase of high-voltage circuit breaker at characteristic position in nth time period, Ex(0) And the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in the first time period is represented.
5. An electric field based insulation monitoring system for a high voltage circuit breaker, comprising: an electric field monitoring device, a relay device, a cloud server and a client terminal,
the number of the electric field monitoring devices is 3, and the electric field monitoring devices are used for respectively monitoring the power frequency electric field intensity amplitude at the three-phase characteristic position of the high-voltage circuit breaker A, B, C in real time and sending monitoring data to the relay device;
the relay device is used for sending the monitoring data to a cloud server;
and the cloud server is used for analyzing the monitoring data so as to identify and evaluate the external insulation degradation condition of the high-voltage circuit breaker, and sending the monitoring data and the evaluation result to the client terminal.
6. The system according to claim 5, wherein 3 electric field monitoring devices are respectively installed outside three bushing flanges of the high-voltage circuit breaker and the installation positions thereof correspond to each other, or are respectively installed at a three-phase transmission mechanism housing of the high-voltage circuit breaker and the installation positions thereof correspond to each other.
7. The system according to claim 6, wherein 3 electric field monitoring devices are respectively installed at the position where the gradient of the electric field intensity outside the three casing flanges of the high-voltage circuit breaker is the most severe, or are respectively installed at the position where the gradient of the electric field intensity outside the three-phase transmission mechanism casing of the high-voltage circuit breaker is the most severe.
8. The system of claim 7, wherein the location where the electric field strength gradient changes most severely is calculated by:
if the electric field monitoring device is installed outside the flange, the calculation is carried out according to the following formula:
wherein, gradE (x, y, h)0) As a space coordinate of (x, y, h)0) A gradient of the electric field strength E of (d); h is0The height of the installation position of the electric field monitoring device; r islimitAn extreme position suitable for mounting on the outer side of the flange; e (h)0) For electric field monitoring devices mounted at h0The electric field strength of (d);
if the electric field monitoring device is installed outside the transmission mechanism, the calculation is carried out according to the following formula:
wherein, gradE ' (x ', y ', h)0') is a space coordinate of (x ', y ', h)0') the gradient of the electric field strength E'; h is0' is the height of the installation place of the electric field monitoring device; x is the number oflimitFor extreme positions, y, suitable for mounting in the direction of the x-axis outside the mechanismlimitThe limit position is suitable for installation in the y-axis direction outside the mechanism; e' (h)0') is an electric field monitoring device arranged at h0The electric field strength of (d).
9. The system of claim 5, wherein the cloud server is configured to:
according to the electric field intensity of the characteristic position of each phase of high-voltage circuit breaker, calculating the change rate of the electric field intensity amplitude compared with two adjacent time periods of the characteristic position of each phase of high-voltage circuit breaker, when the value is stable and basically remains unchanged in a preset time period, completing self-checking, and initializing a clock to be 0;
dividing the total monitoring time into a plurality of same time intervals, and monitoring to obtain the average value of the electric field intensity amplitude of the characteristic position of each phase of high-voltage circuit breaker in each time interval;
according to the average value of the electric field intensity amplitude of each phase high-voltage circuit breaker characteristic position in each time interval, solving the electric field intensity change rate in the adjacent time interval and the electric field intensity change rate in the total time interval of each phase high-voltage circuit breaker characteristic position;
and judging the external insulation degradation condition of the high-voltage circuit breaker based on a set standard according to the electric field strength change rate in the adjacent time interval at the characteristic position of each phase of high-voltage circuit breaker and the electric field strength change rate in the total time interval.
10. The system of claim 5, wherein the electric field monitoring device comprises a d-dot electric field probe, an amplification and filtering module, a first Lora communication module, a first MCU module, a first lithium battery, a first battery voltage acquisition module, and a first charge protection module, wherein,
the d-dot electric field probe is used for detecting the power frequency electric field intensity and sending a power frequency electric field signal to the amplifying and filtering module;
the amplifying and filtering module is used for amplifying the power frequency electric field signal, filtering out high-frequency electromagnetic interference components and outputting the high-frequency electromagnetic interference components to an ADC port of the first MCU module;
the first battery voltage acquisition module is used for converting the voltage of the first lithium battery into an ADC (analog to digital converter) signal which can be read by the first MCU module;
the first MCU module is used for collecting a power frequency electric field signal of the ADC port, eliminating external interference and then transmitting the power frequency electric field signal to the first Lora communication module; the battery voltage signal acquisition module is used for acquiring a battery voltage signal of the ADC port and transmitting the battery voltage signal to the first Lora communication module;
the first Lora communication module is used for transmitting the power frequency electric field signal and the battery voltage signal to the relay device;
the first lithium battery supplies power to the amplifying and filtering module, the first Lora communication module and the first MCU module;
the first charging protection module is used for preventing the first lithium battery from being overcharged when the first lithium battery is charged.
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