CN210803591U - High-precision synchronous acquisition device for monitoring extra-high voltage converter station sleeve - Google Patents
High-precision synchronous acquisition device for monitoring extra-high voltage converter station sleeve Download PDFInfo
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Abstract
A high-precision synchronous acquisition device for monitoring an extra-high voltage converter station sleeve comprises a signal conditioning circuit, a signal acquisition circuit and a signal processing circuit, wherein the signal processing circuit is used for inputting a high-precision zero-flux sleeve end screen grounding small current signal acquired by an extra-high voltage sleeve end screen adapter; a parallel analog-to-digital conversion unit; the photoelectric conversion module is responsible for converting baseband signals suitable for optical fiber transmission; the configuration unit is used for stamping a time mark on the synchronous data packet; the CPU processor completes the time synchronization process according to the time mark information of the received and sent synchronous data packet; the voltage-controlled crystal oscillator outputs the same control frequency to the CPU processor and the configuration unit respectively, and eliminates the frequency offset of the voltage-controlled crystal oscillator in real time through automatic frequency control to finish high-precision synchronous acquisition. The utility model discloses a synchronous collection system of high accuracy has improved the time to precision of configuration unit, provides the synchronous sampling data of high accuracy for sleeve pipe dielectric loss relative measurement method moreover to sleeve pipe dielectric loss measurement accuracy has been improved relatively.
Description
Technical Field
The utility model relates to an electric power internet of things technical field, concretely relates to a high accuracy synchronous acquisition device for monitoring of special high voltage converter station sleeve pipe.
Background
The sleeve on the network side of the converter station is easily affected by high dielectric and thermal stress, the failure of the sleeve is serious, and the sleeve is forced to be shut down due to serious hazards such as fire and the like, so that the online monitoring of the sleeve is an indispensable part of an online monitoring system of core power equipment. Generally, the insulation state of the bushing is judged according to the technical means such as the tangent value of the dielectric loss of the bushing, the capacitance, the insulation resistance, the dielectric loss of the bushing end screen and the like, and different insulation parameters reflect the insulation state of the bushing in different aspects. The dielectric loss value is the ratio of the active component and the reactive component of the current in the dielectric medium under the action of alternating voltage, and under certain voltage and frequency, the dielectric loss value reflects the energy loss in unit volume in the dielectric medium and is related to the volume size and the size of the dielectric medium; the dielectric loss value is one of effective methods for evaluating the insulation condition of the extra-high voltage equipment. However, factors affecting the accuracy of the dielectric loss value measurement are many:
(1) the insulation performance of the insulation material can change along with the change of the temperature due to the temperature and the humidity of the environment, the relative humidity of the air is high, and a low-resistance conductive loop is formed on the insulation surface, so that the dielectric loss value is obviously changed.
(2) The frequency of the power grid is not constant and often fluctuates within a certain range in the actual operation of the power grid due to the continuous change of the frequency of the power grid, so that sampling errors are brought, and phase calculation errors are increased.
(3) The PT angular difference, PT secondary voltage can generate phase change relative to primary voltage due to the angular difference, thereby influencing the measurement of dielectric loss value.
As can be seen from the above, there are many factors that affect casing dielectric loss measurement, and therefore, it is difficult to accurately measure the absolute dielectric loss of the casing. The relative measurement method measures the grounding current signals of a plurality of bushings running in the same phase, measures the relative tangent value between devices by using the mutual reference signals of the bushing grounding current signals, and judges the insulation condition of the bushings according to the change of the relative dielectric loss tangent angle. However, the basic requirement of the relative measurement method is high-precision synchronous sampling, and therefore, it is obviously of great importance to research a high-precision synchronous acquisition device to improve the accuracy of monitoring the insulation condition of the ultra-high voltage bushing.
Disclosure of Invention
The utility model discloses a solve the above-mentioned problem that prior art exists, provide a high accuracy synchronous collection system for extra-high voltage current conversion station sleeve pipe monitoring.
In order to achieve the above object, the utility model provides a high accuracy synchronous acquisition device for monitoring of extra-high voltage converter station sleeve pipe, include:
the signal conditioning circuit is connected with an extra-high voltage sleeve end screen adapter on a sleeve of an extra-high voltage converter station so as to input a high-precision zero-flux sleeve end screen grounding small current signal acquired by the extra-high voltage sleeve end screen adapter;
the signal conditioning circuit is used for inputting data signals acquired by the extra-high voltage sleeve tap adapter into the parallel analog-to-digital conversion unit after jitter elimination, filtering, protection and amplification processing;
the photoelectric conversion module is used for being in communication connection with an external switchboard with an IEEE1588 protocol so as to be responsible for converting baseband signals suitable for optical fiber transmission;
the configuration unit is provided with a clock synchronization module based on an IEEE1588 clock synchronization technology, the clock synchronization module is connected with the photoelectric conversion module and is used for stamping a time mark on a synchronous data packet from an IEEE 1588-supporting switch, the sending clock is synchronous with the receiving clock, and the phase error of the time mark of the sent synchronous data packet and the clock phase error of the received synchronous data packet are guaranteed to be zero; the configuration unit is also connected with the parallel analog-to-digital conversion unit to output a periodic sampling pulse aligned with a 1PPS boundary as a sampling starting signal of the parallel analog-to-digital conversion unit;
the CPU is connected with the parallel analog-to-digital conversion unit, so that when the parallel analog-to-digital conversion unit completes the conversion of the sampled data signal from the extra-high voltage bushing end screen adapter, the parallel analog-to-digital conversion unit outputs a pulse signal to inform the CPU to start the DMA to move the converted sampled data signal; the CPU processor is internally provided with a precise time protocol unit which is connected with the configuration unit so as to complete a time synchronization process according to the time mark information of the received and sent synchronous data packet;
and the voltage-controlled crystal oscillator is connected with the CPU processor and the configuration unit so as to output the same control frequency to the CPU processor and the configuration unit respectively, and the frequency offset of the voltage-controlled crystal oscillator is eliminated in real time through automatic frequency control so as to complete high-precision synchronous acquisition, wherein the synchronous precision can be controlled within 100 nanoseconds.
As the utility model discloses a further preferred technical scheme, the quantity of extra-high voltage sleeve pipe end screen adapter is three, and extra-high voltage converter station has respectively with the A looks of power, B looks, the corresponding three pipe box of C, every extra-high voltage sleeve pipe end screen adapter respectively corresponds a sleeve pipe of extra-high voltage converter station, signal conditioning circuit has three signal conditioning unit, every signal conditioning unit corresponds and connects one extra-high voltage sleeve pipe end screen adapter.
As a further preferred technical solution of the present invention, the CPU processor further has therein a frequency control unit connected to the precision time protocol unit, and the frequency control unit is connected to the voltage-controlled crystal oscillator.
As a further preferred technical scheme of the utility model, still be connected with the analog conversion unit on the voltage-controlled crystal oscillator, the voltage-controlled crystal oscillator passes through the analog conversion unit is connected to the frequency control unit of CPU treater.
As a further preferred technical solution of the present invention, a 12-bit digital interface is provided on the CPU processor, and the frequency control unit passes through the digital interface and the analog conversion unit are connected.
The utility model discloses a high accuracy synchronous collection system for extra-high voltage converter station sleeve pipe monitoring, through the improvement to the synchronous data package time scale record point that possesses the IEEE1588 agreement, and guaranteed the synchronization of sending clock and receiving clock, make it improve the timing precision of configuration unit, and simultaneously, this device still can be through the initial synchronization to the time convergence back, again according to two continuous synchronous data package to the time error, adjust voltage-controlled crystal oscillator's frequency, the timing precision has further been improved, make the time error between the synchronous collection system under the same switch within 100 nanoseconds, thereby for the sleeve pipe is situated between and is decreased the relative measurement method and provide the synchronous sampling data of high accuracy, and then the relative dielectric loss measurement accuracy of sleeve pipe has been improved.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a block diagram showing an example of a high-precision synchronous collecting device for monitoring an extra-high voltage converter station casing according to the present invention;
FIG. 2 is a schematic diagram of a time synchronization process performed during the operation of a precision time protocol unit;
the purpose of the present invention is to provide a novel and improved method and apparatus for operating a computer.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description. In the preferred embodiments, the terms "upper", "lower", "left", "right", "middle" and "a" are used for the sake of clarity only, and are not intended to limit the scope of the invention, its relative relationship between the terms and their derivatives, and the scope of the invention should be understood as being limited by the claims.
As shown in fig. 1, the high-precision synchronous acquisition device for monitoring the casing of the ultra-high voltage converter station includes:
the signal conditioning circuit is connected with an extra-high voltage sleeve end screen adapter on a sleeve of an extra-high voltage converter station so as to input a high-precision zero-flux sleeve end screen grounding small current signal collected by the extra-high voltage sleeve end screen adapter, wherein the extra-high voltage sleeve end screen adapter adopts an active zero-flux technology, the detection precision of a small current sensor can be effectively improved, and besides a special alloy with high initial permeability and low loss is selected as an iron core, full-automatic tracking compensation is carried out on the excitation magnetic potential in the iron core by means of an electronic signal processing technology, so that the iron core is kept to work in a near-ideal zero-flux state;
the signal conditioning circuit is used for inputting data signals acquired by the extra-high voltage sleeve tap adapter into the parallel analog-to-digital conversion unit after jitter elimination, filtering, protection and amplification processing;
the photoelectric conversion module is used for being in communication connection with an external switchboard with an IEEE1588 protocol so as to be responsible for converting baseband signals suitable for optical fiber transmission;
the configuration unit is provided with a clock synchronization module based on an IEEE1588 clock synchronization technology, the clock synchronization module is connected with the photoelectric conversion module and is used for stamping a time mark on a synchronous data packet from an IEEE 1588-supporting switch, the sending clock is synchronous with the receiving clock, and the phase error of the time mark of the sent synchronous data packet and the clock phase error of the received synchronous data packet are guaranteed to be zero; the configuration unit is also connected with the parallel analog-to-digital conversion unit to output a periodic sampling pulse aligned with a 1PPS boundary as a sampling starting signal of the parallel analog-to-digital conversion unit;
the CPU is connected with the parallel analog-to-digital conversion unit, so that when the parallel analog-to-digital conversion unit completes the conversion of the sampled data signal from the extra-high voltage bushing end screen adapter, the parallel analog-to-digital conversion unit outputs a pulse signal to inform the CPU to start the DMA to move the converted sampled data signal;
the CPU processor has a precise time protocol unit therein, and the precise time protocol unit is connected to the configuration unit to complete a time synchronization process according to the time stamp information of the received and transmitted synchronization packet, as shown in fig. 2, the specific process is as follows:
the calculation formula of the time delay of sending the Sync data packet from the switch to the synchronous acquisition device is as follows:
delay _ req is sent from the synchronous acquisition device to the switch, and the calculation formula is as follows:
because of the symmetry of the communication path, the time delays in the two transmission directions are consistent, so the time difference between the switch and the synchronous acquisition device is as follows:
configuration unit transmit clock and receive clock synchronization, cancellation
And
phase error of time mark recording, but
Errors caused by crystal oscillator frequency drift are not considered;
and the voltage-controlled crystal oscillator is connected with the CPU processor and the configuration unit so as to output the same control frequency to the CPU processor and the configuration unit respectively, and the frequency offset of the voltage-controlled crystal oscillator is eliminated in real time through automatic frequency control so as to complete high-precision synchronous acquisition, wherein the synchronous precision can be controlled within 100 nanoseconds.
In specific implementation, the number of the extra-high voltage sleeve end screen adapters is three, the extra-high voltage converter station is provided with three pipe sleeves corresponding to an A phase, a B phase and a C phase of a power supply respectively, each extra-high voltage sleeve end screen adapter corresponds to one sleeve of the extra-high voltage converter station, the signal conditioning circuit is provided with three signal conditioning units, and each signal conditioning unit is correspondingly connected with one extra-high voltage sleeve end screen adapter.
In specific implementation, the CPU processor further includes a frequency control unit connected to the precise time protocol unit, the frequency control unit is connected to the voltage controlled crystal oscillator, the voltage controlled crystal oscillator is further connected to an analog conversion unit, the voltage controlled crystal oscillator is connected to the frequency control unit of the CPU processor through the analog conversion unit, the CPU processor is provided with a 12-bit digital interface, and the frequency control unit is connected to the analog conversion unit through the digital interface. The frequency control unit records twice according to the precise time protocol unit
The time difference is used as input, the difference is filtered and smoothed, and the crystal oscillator frequency offset of the device is calculated, namely:
here, the
=0.5, time difference after filteringAccording to the characteristic curve of the voltage-controlled oscillator, the digital control word is converted into a digital control word, and the digital control word is output to the analog conversion unit through a 12-bit digital interface so as to correct the frequency error of the voltage-controlled crystal oscillator.
In specific implementation, the analog conversion unit is used for converting the control word input by the frequency unit into an analog voltage and outputting the analog voltage to a control voltage pin of the voltage-controlled crystal oscillator; the output frequency of the vco is linear with the input voltage, and the slope of the input voltage and the output frequency can be obtained by the following formula:
according to the slope
And the CPU processor fits a calibrated control word table to realize the accurate calibration of the frequency offset, and the frequency accuracy of the voltage-controlled crystal oscillator is below 0.01ppm after the calibration.
The utility model discloses a high accuracy synchronous acquisition device for extra-high voltage converter station sleeve pipe monitoring has following function:
the configuration unit is connected with a switch with an IEEE1588 protocol through an optical fiber, an Ethernet protocol and an accurate time protocol are realized, the configuration unit is provided with an EEE1588 physical layer so that a synchronous data packet with the IEEE1588 protocol can be analyzed, and receiving and sending time marks are recorded when the synchronous data packet is analyzed;
the configuration unit synchronizes a sending clock and a receiving clock in the communication process, and eliminates the phase error of the time scale of sending the synchronous data packet and the time scale of receiving the data packet;
according to the precise time protocol, the method realizes the initial time synchronization (namely the initial synchronization process, the synchronization precision is required to be 1 microsecond) with the switch with the IEEE1588 protocol, and the initial synchronization process is as follows:
interval time for sending SYNC data packet by the exchange is fixed
The time scale of the synchronous acquisition device receiving the nth packet SYNC data packet is set as
The formula for calculating the initial synchronization error is as follows:
by cumulative averaging
Rear output
To adjust the local timer to wait for the average synchronization error
The convergence is below one microsecond, and the average time difference of two continuous received synchronous data packets is output.
Frequency control unit in CPU processing according to received average time difference
The treatment process comprises the following steps:
mean time difference between transformation
To frequency error
；
Calculating a control voltage according to a slope formula of the voltage-controlled crystal oscillator;
generating a mapping table of a 12-bit digital value and an analog control voltage according to a slope curve of the voltage-controlled crystal oscillator, inquiring the mapping table to generate a digital control word, and controlling the DA converter to complete frequency control.
Configuring cell outputs to align with 1PPS boundariesThe sampling rate is ensured to be the interval frequency of SYNC data packet transmission
Integer multiples of.
The utility model discloses an improvement to the synchronous data package time scale record point that possesses the IEEE1588 agreement, and guaranteed the synchronization of sending clock with receiving the clock, make it improve the time setting precision of configuration unit, and simultaneously, this device still can be through the time setting convergence back of just synchronizing, again according to two continuous synchronous data package time setting errors, adjust voltage-controlled crystal oscillator's frequency, the time setting precision has further been improved, make the time error between the synchronous acquisition device under the same switch within 100 nanoseconds, thereby for the sleeve pipe is situated between and is decreased the relative measurement method and provide the synchronous sampling data of high accuracy, and then the relative dielectric loss measurement accuracy of sleeve pipe has been improved.
Although specific embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that these are merely examples and that many changes and modifications may be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims.
Claims (5)
1. The utility model provides a high accuracy synchronous acquisition device for extra-high voltage converter station sleeve pipe monitoring which characterized in that includes:
the signal conditioning circuit is connected with an extra-high voltage sleeve end screen adapter on a sleeve of an extra-high voltage converter station so as to input a high-precision zero-flux sleeve end screen grounding small current signal acquired by the extra-high voltage sleeve end screen adapter;
the signal conditioning circuit is used for inputting data signals acquired by the extra-high voltage sleeve tap adapter into the parallel analog-to-digital conversion unit after jitter elimination, filtering, protection and amplification processing;
the photoelectric conversion module is used for being in communication connection with an external switchboard with an IEEE1588 protocol so as to be responsible for converting baseband signals suitable for optical fiber transmission;
the configuration unit is provided with a clock synchronization module based on an IEEE1588 clock synchronization technology, the clock synchronization module is connected with the photoelectric conversion module and is used for stamping a time mark on a synchronous data packet from an IEEE 1588-supporting switch, synchronizing a sending clock with a receiving clock and ensuring that the clock phase error of the time mark of the sending synchronous data packet and the clock phase error of the receiving synchronous data packet are zero; the configuration unit is also connected with the parallel analog-to-digital conversion unit to output a periodic sampling pulse aligned with a 1PPS boundary as a sampling starting signal of the parallel analog-to-digital conversion unit;
the CPU is connected with the parallel analog-to-digital conversion unit, so that when the parallel analog-to-digital conversion unit completes the conversion of the sampled data signal from the extra-high voltage bushing end screen adapter, the parallel analog-to-digital conversion unit outputs a pulse signal to inform the CPU to start the DMA to move the converted sampled data signal; the CPU processor is internally provided with a precise time protocol unit which is connected with the configuration unit so as to complete a time synchronization process according to the time mark information of the received and sent synchronous data packet;
and the voltage-controlled crystal oscillator is connected with the CPU processor and the configuration unit so as to output the same control frequency to the CPU processor and the configuration unit respectively, and the frequency offset of the voltage-controlled crystal oscillator is eliminated in real time through automatic frequency control so as to complete high-precision synchronous acquisition, wherein the synchronous precision can be controlled within 100 nanoseconds.
2. The high-precision synchronous acquisition device for extra-high voltage converter station sleeve monitoring according to claim 1, wherein the number of the extra-high voltage sleeve end screen adapters is three, the extra-high voltage converter station has three sleeve pipes corresponding to phase a, phase B and phase C of a power supply respectively, each extra-high voltage sleeve end screen adapter corresponds to one sleeve pipe of the extra-high voltage converter station, the signal conditioning circuit has three signal conditioning units, and each signal conditioning unit is correspondingly connected with one extra-high voltage sleeve end screen adapter.
3. The high-precision synchronous acquisition device for extra-high voltage converter station bushing monitoring according to claim 1, wherein the CPU processor is internally provided with a frequency control unit connected with the precision time protocol unit, and the frequency control unit is connected to the voltage-controlled crystal oscillator.
4. The high-precision synchronous acquisition device for extra-high voltage converter station bushing monitoring according to claim 3, wherein an analog conversion unit is further connected to the voltage controlled crystal oscillator, and the voltage controlled crystal oscillator is connected to the frequency control unit of the CPU processor through the analog conversion unit.
5. The high-precision synchronous acquisition device for extra-high voltage converter station bushing monitoring according to claim 4, wherein a 12-bit digital interface is provided on the CPU processor, and the frequency control unit is connected with the analog conversion unit through the digital interface.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110441617A (en) * | 2019-09-10 | 2019-11-12 | 上海远观物联网科技有限公司 | A kind of high-precise synchronization acquisition device for ultra-high voltage converter station casing monitoring |
| CN112858767A (en) * | 2020-12-22 | 2021-05-28 | 国网宁夏电力有限公司检修公司 | High-precision synchronous acquisition device for monitoring extra-high voltage converter station sleeve |
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2019
- 2019-09-10 CN CN201921495665.9U patent/CN210803591U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110441617A (en) * | 2019-09-10 | 2019-11-12 | 上海远观物联网科技有限公司 | A kind of high-precise synchronization acquisition device for ultra-high voltage converter station casing monitoring |
| CN112858767A (en) * | 2020-12-22 | 2021-05-28 | 国网宁夏电力有限公司检修公司 | High-precision synchronous acquisition device for monitoring extra-high voltage converter station sleeve |
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