Distribution automation terminal synchronous sampling method using satellite time synchronization

Abstract

The invention discloses a power distribution automation terminal synchronous sampling method using satellite time synchronization, and belongs to the technical field of power distribution automation and power grid monitoring. The method is characterized by comprising the following steps: step a, configuring a sampling system at a power distribution automation terminal; b, a sampling system collects power grid operation state data and satellite signals; c, configuring a timer and calculating an actual sampling interval; step d, starting a timer for continuous sampling; step e, judging whether second pulse interruption is generated or not; and f, the power distribution automation terminal generates a wave recording file by using the time stamp marked by each sampling point. According to the power distribution automation terminal synchronous sampling method utilizing satellite time synchronization, high-precision synchronous sampling among the terminals is realized, so that the accuracy and consistency of sampled data are greatly improved, the flexibility and applicability of the whole system are effectively improved, and the requirements of different application scenes can be better met.

Description

Technical Field

[0001] The invention discloses a synchronous sampling method for a distribution automation terminal using satellite time synchronization, belonging to the technical field of distribution automation and power grid monitoring. Background Art

[0002] In today's distribution automation and power grid monitoring field, synchronous sampling technology is of irreplaceable importance for accurately grasping the operation status of the power grid. In the existing technology, if the distribution automation terminal is to have the synchronous sampling capability, it is usually necessary to carry out large-scale hardware transformation of the terminal and add complex additional functional modules. This not only leads to a sharp increase in costs, but also faces many technical difficulties in the actual implementation process, making it difficult to implement.

[0003] In addition, the traditional synchronous sampling method often relies on fixed frequency triggering AD sampling, and requires a special additional frequency calculation module to track grid frequency changes. This method places stringent requirements on the hardware structure and functional modules of the distribution automation terminal, resulting in poor compatibility. Especially for those new distribution automation terminals that support dynamic frequency triggered AD sampling, it is difficult for traditional methods to achieve effective synchronous sampling functions. At the same time, the traditional synchronous sampling scheme has high real-time requirements for distribution automation terminals. This makes it difficult for some terminals that are not real-time but also require precise sampling data to meet the requirements, limiting their application in a wider range of scenarios.

[0004] A Chinese invention patent with application number 202410209756.0 and application date of February 26, 2024, and patent name "A method for wide-area synchronous sampling of primary and secondary integrated pole-mounted circuit breakers" discloses a technical solution. In this technical solution, by adopting a variable sampling interval method, the residual error caused by the non-integer division of the crystal oscillator frequency and the ideal sampling frequency can be effectively compensated for the sampling time error, and the equivalent sampling rate is close to the ideal sampling rate. By using the high-precision second pulse PPS generated by the Beidou receiver as the time reference, the crystal oscillator frequency is measured in real time, and the sampling control parameter TCP is adaptively corrected. Thereby, the residual error caused by the crystal oscillator frequency offset can be effectively suppressed, thereby improving the anti-interference and stability of synchronous sampling. However, when implementing this technical solution, there is a problem of large amount of calculation. Therefore, designing a simple, reliable and highly operational technical solution to realize synchronous sampling of distribution automation terminals has become a problem to be solved in this field. Summary of the invention

[0005] The technical problem to be solved by the present invention is: to overcome the shortcomings of the prior art and provide a method for realizing high-precision synchronous sampling between terminals, thereby greatly improving the accuracy and consistency of the sampled data, and effectively improving the flexibility and applicability of the entire system, and being able to better meet the needs of different application scenarios. The method of synchronous sampling of distribution automation terminals using satellite timing.

[0006] The technical solution adopted by the present invention to solve the technical problem is: the distribution automation terminal synchronous sampling method using satellite time synchronization is characterized by comprising the following steps:

[0007] Step a, configuring a sampling system for each distribution automation terminal in the power grid;

[0008] Step b, the sampling system collects power grid operation status data and satellite signals;

[0009] Step c, the main control chip sets the timer overflow upper limit according to the sampling interval calculated according to the design requirements, and calculates the actual sampling interval;

[0010] Step d, the timer sends a trigger signal when it starts, and when the timer count reaches its overflow upper limit, the timer is reset and started again when it overflows, and the grid signal is continuously sampled;

[0011] Step e, determining whether a pulse-per-second interruption is generated, recording the current count of the timer when the pulse-per-second interruption is triggered, determining the sampling point adjacent to the pulse-per-second according to the actual sampling interval and the time represented by this pulse-per-second, and calculating the timestamp of the adjacent sampling point after the analog-to-digital conversion result of the adjacent sampling point in the sampling system is completed, and binding it to the sampling result; when the pulse-per-second interruption is not generated, collecting the analog-to-digital conversion result in the sampling system, and then calculating the timestamp of the subsequent sampling point, and binding it to the sampling result;

[0012] Step f: the distribution automation terminal generates a waveform recording file using the timestamp marked at each sampling point.

[0013] Preferably, in step a, the sampling system includes a main control module, an analog-to-digital conversion module, a mutual inductor and a satellite receiving module, a satellite receiving antenna is installed on the satellite receiving module, the output end of the satellite receiving module is connected to the input end of the main control module, the main control module is bidirectionally connected to the analog-to-digital conversion module, the primary side of the mutual inductor is connected to the power grid, and the secondary side of the mutual inductor is connected to the analog signal input port of the analog-to-digital conversion module.

[0014] Preferably, in step c, the calculation formula of the actual sampling interval T is: T = N / Fs,

[0015] Among them, Fs is the timer operating frequency, and N is the actual configured timer overflow upper limit:

[0016] N = Round (Fs / (f*np)),

[0017] Wherein, f is the grid frequency, the sampling frequency is np points per cycle, and Round() indicates rounding operation.

[0018] Preferably, in step e, the PPS adjacent sampling point is defined as the PPS sampling point closest to the PPS interruption. When the PPS interruption moment is less than or equal to half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the current sampling point; when the PPS interruption moment is more than half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the next sampling point of the current sampling point.

[0019] Preferably, in step e, the method for calculating the timestamp of the second pulse near the sampling point is:

[0020] When the adjacent sampling point is the next sampling point, the calculation formula of the PPS adjacent sampling point timestamp Sp is: Sp = Tpps + (N-Np) * T,

[0021] At this time, wait for the next sampling to end, and after the analog-to-digital conversion module completes the analog-to-digital conversion, bind this timestamp to the sampling result;

[0022] When the adjacent sampling point is the current sampling point, the calculation formula of the PPS adjacent sampling point timestamp Sp is: Sp = Tpps-Np*T,

[0023] At this time, wait for the current sampling point to end and bind this timestamp to the sampling result;

[0024] Among them, Sp is the timestamp of the PPS adjacent sampling point, TPPS is the time information represented by this PPS, N is the actual configured timer overflow upper limit, Np is the timer count of the PPS interrupt record, and T is the actual sampling interval.

[0025] Preferably, in step e, the calculation formula of the subsequent sampling point timestamp is: S=Sp+n*T;

[0026] Where n is the count of subsequent sampling points starting from the PPS adjacent sampling point, T is the actual sampling interval, and Sp is the timestamp of the PPS adjacent sampling point.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The distribution automation terminal synchronous sampling method using satellite timing disclosed in the present application equips the distribution automation terminal with a satellite signal receiver, and with the help of the highly accurate clock signal of the satellite system, realizes high-precision synchronous sampling between the terminals, thereby greatly improving the accuracy and consistency of the sampled data, which is conducive to further realizing the accurate monitoring and analysis of the operation status of the power grid.

[0029] The synchronous sampling method of distribution automation terminal using satellite timing in this application solves the problems of high terminal hardware requirements, complex functional modules and poor compatibility of existing synchronous sampling technologies. Whether the distribution automation terminal uses dynamic or fixed frequency trigger AD sampling, it can easily realize the synchronous sampling function, greatly improving the versatility and adaptability of the method.

[0030] By marking each sampling point with an accurate timestamp, the distribution automation terminal with low real-time performance can first cache the sampling data and then perform subsequent processing at the appropriate time, effectively improving the flexibility and applicability of the entire system and better meeting the needs of different application scenarios.

[0031] It has unique advantages in achieving the upgrade of the synchronous sampling function of distribution automation terminals. The synchronous sampling function can be improved by simply adding a satellite timing module to the terminal. Compared with the traditional method that requires large-scale hardware transformation and addition of complex functional modules to the terminal, it greatly simplifies the upgrade process and significantly reduces the transformation cost. This low-cost and easy-to-implement feature enables many existing distribution automation terminals to optimize the synchronous sampling function with lower investment, showing extremely high practical value in actual application scenarios, effectively improving resource utilization efficiency, and promoting the popularization and application of distribution automation technology.

[0032] Strong sampling compatibility and flexible function expansion: In the past, distribution automation terminals faced many limitations in achieving synchronous sampling, especially in the sampling frequency triggering method. Traditional methods mostly rely on fixed frequency triggered AD sampling, and require an additional frequency calculation module to track the grid frequency, which has poor compatibility with different types of terminals. The present invention breaks through this limitation. Whether it is a distribution automation terminal that uses dynamic frequency triggered AD sampling or fixed frequency triggered AD sampling, the present invention can achieve accurate synchronous sampling function. This feature greatly broadens the scope of application of the present invention, allowing various types of distribution automation terminals to be unified in the synchronous sampling function, providing solid technical support for the integration and optimization of the power grid monitoring system, and effectively improving the flexibility and adaptability of the entire distribution automation system.

[0033] Reduce real-time dependence and achieve efficient cache processing: In actual operation, distribution automation terminals have varying requirements for real-time performance. The traditional synchronous sampling method has high requirements for terminal real-time performance, which limits the application of some terminals that do not have high real-time performance but still require accurate data sampling. The present invention cleverly solves this problem by marking a timestamp for each sampling point. Distribution automation terminals with low real-time performance can first cache the sampled data, and then centrally process it at the appropriate time. This cache post-processing method not only reduces the stringent requirements for terminal real-time performance and improves the compatibility of the terminal, but also optimizes system resource allocation, allowing the system to more efficiently respond to sampling tasks with different real-time requirements, thereby improving the operating efficiency and stability of the entire distribution automation system under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The present invention is a flow chart of the synchronous sampling method of distribution automation terminals using satellite timing.

[0035] Figure 2 The schematic diagram of the sampling system for the synchronous sampling method of distribution automation terminals using satellite timing is shown in the figure.

[0036] Figure 3 Schematic diagram of PPS and adjacent sampling point determination for distribution automation terminal synchronous sampling method using satellite timing. DETAILED DESCRIPTION

[0037] Figures 1 to 3 The best embodiment of the present invention is shown below in conjunction with the attached Figures 1 to 3 The present invention is further described.

[0038] like Figure 1 As shown, a distribution automation terminal synchronous sampling method using satellite timing includes the following steps:

[0039] Step 1001, configuring a sampling system at a distribution automation terminal;

[0040] Configure sampling systems for each distribution automation terminal in the power grid, such as Figure 2 As shown, the sampling system includes a main control module, an analog-to-digital conversion module, a transformer and a satellite receiving module. A satellite receiving antenna is installed on the satellite receiving module, the output end of the satellite receiving module is connected to the input end of the main control module, the main control module is bidirectionally connected to the analog-to-digital conversion module, the primary side of the transformer is connected to the power grid, and the secondary side of the transformer is connected to the analog signal input port of the analog-to-digital conversion module.

[0041] The satellite receiving module receives the signal of GPS or Beidou system. The transformer collects the grid operation status data of the grid, which is sampled by the analog-to-digital conversion module and sent to the main control module, and the main control module calculates the grid terminal telesignaling information and telemetry information.

[0042] Figure 2 The central control module also uses the main control chip in the distribution automation terminal, that is, the satellite receiving module, analog-to-digital conversion module and mutual inductor are configured inside the distribution automation terminal; Figure 2 The central control module can also be another main control module different from the main control chip in the distribution automation terminal. Figure 2 The circuit structure shown in is used as a separate product, and the two main control modules communicate through the communication interface reserved by the distribution automation terminal.

[0043] Step 1002, the sampling system collects power grid operation status data and satellite signals;

[0044] The satellite receiving module receives signals from GPS or Beidou system, and provides timing information and high-precision pulse per second (PPS). The rising edge of the PPS pulse is the second moment, with an accuracy of 10ns; after the PPS signal, the timing information corresponding to the current PPS is sent to the main control chip through the NMEA protocol of the RS232 interface.

[0045] Step 1003, configure the timer and calculate the actual sampling interval;

[0046] The main control chip calculates the sampling interval according to the design requirements, sets the timer overflow upper limit, and calculates the actual sampling interval.

[0047] The sampling of the analog-to-digital conversion module is directly controlled by the main control chip, and the sampling delay is ΔT1. Take the grid frequency f, the sampling frequency is np points per cycle, then the theoretical sampling period is 1 / (f*np), the main control chip timer operating frequency is Fs, then the theoretical timer overflow upper limit is Nr=Fs / (f*np), the main control chip timer overflow upper limit can only be set to an integer, then after rounding the theoretical timer overflow upper limit Nr, the actual configured timer overflow upper limit is obtained: N=Round(Fs / (f*np)), then the actual sampling interval is T=N / Fs.

[0048] Step 1004, start the timer to continue sampling;

[0049] The timer sends a trigger signal when it starts. When the timer count reaches its overflow upper limit, the timer is reset and started again when it overflows to continuously sample the power grid signal.

[0050] Step 1005, whether a PPS interruption is generated;

[0051] Determine whether a PPS interruption is generated. If a PPS interruption is generated, execute step 1006; if no PPS interruption is generated, execute step 1008.

[0052] Step 1006, read the timer count to determine the approaching sampling point;

[0053] When the PPS interrupt is triggered, the current count of the timer is recorded, and the PPS near sampling point is estimated based on the actual sampling interval and the time represented by this PPS.

[0054] The PPS adjacent sampling point is defined as the PPS sampling point closest to the PPS interruption. When the PPS interruption moment is less than or equal to half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the current sampling point; when the PPS interruption moment is more than half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the next sampling point of the current sampling point, such as Figure 3 shown.

[0055] Step 1007, collect nearby sampling points, calculate and mark them as timestamps;

[0056] When the PPS interrupt is triggered, the moment TPPS represented by this PPS is obtained in combination with the NMEA information of the RS232 interface. The main control chip interrupt processing delay is ΔT2, and the actual moment is TPPS+ΔT2. At the same time, the main control chip timer count Np is obtained. Since the timer is in the running state when the interrupt occurs, the time is calculated by Np. In theory, there is a maximum error of 1 / Fs. Since the timer operating frequency Fs is generally large, this error is ignored here.

[0057] The calculation method of the PPS adjacent sampling point timestamp Sp is:

[0058] (1) The adjacent sampling point is the next sampling point, that is At this time, the calculation formula of the PPS near sampling point timestamp Sp is: Sp = Tpps + (N-Np) * T,

[0059] At this time, wait for the next sampling to end, and after the analog-to-digital conversion module completes the analog-to-digital conversion, bind this timestamp to the sampling result.

[0060] (2) The adjacent sampling point is the current sampling point, that is, At this time, the calculation formula of the PPS near sampling point timestamp Sp is: Sp = Tpps-Np*T,

[0061] At this time, wait for the current sampling point to end (if it has ended, there is no need to wait), and bind this timestamp to the sampling result.

[0062] Among them, Sp is the timestamp of the PPS adjacent sampling point, TPPS is the time information represented by this PPS, N is the actual configured timer overflow upper limit, Np is the timer count of the PPS interrupt record, and T is the actual sampling interval.

[0063] Step 1008, collect the analog-to-digital conversion results, calculate and mark them as the timestamps of subsequent sampling points;

[0064] When no PPS interruption occurs, the timestamp of the subsequent sampling points is calculated by the timestamp of this point + the actual sampling interval. Each PPS re-corrects the timestamp to eliminate the accumulated error.

[0065] The calculation formula of the subsequent sampling point timestamp S is: S = Sp + n * T;

[0066] Where n is the count of subsequent sampling points starting from the PPS adjacent sampling point, T is the actual sampling interval, and Sp is the timestamp of the PPS adjacent sampling point.

[0067] At this time, wait for the sampling to end. After the analog-to-digital conversion module completes the analog-to-digital conversion, the subsequent sampling point timestamp is bound to the sampling result.

[0068] Step 1009, end;

[0069] The distribution automation terminal uses the timestamp marked at each sampling point together with necessary information such as telesignals to generate a recording file. Each distribution automation terminal uses this timestamp to record the recording file to achieve synchronous sampling.

[0070] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for synchronous sampling of distribution automation terminals using satellite timing, characterized in that: The steps include: Step a, configuring a sampling system for each distribution automation terminal in the power grid; Step b, the sampling system collects power grid operation status data and satellite signals; Step c, the main control chip sets the timer overflow upper limit according to the sampling interval calculated according to the design requirements, and calculates the actual sampling interval; Step d, the timer sends a trigger signal when it starts, and when the timer count reaches its overflow upper limit, the timer is reset and started again when it overflows, and the grid signal is continuously sampled; Step e, determining whether a second pulse interrupt is generated, recording the current count of the timer when the second pulse interrupt is triggered, determining the second pulse near the sampling point according to the actual sampling interval and the time represented by this second pulse, and calculating the near sampling point timestamp after the analog-to-digital conversion result of the near sampling point in the sampling system is completed, and binding it with the sampling result; When no pulse-per-second interruption occurs, the analog-to-digital conversion results in the sampling system are collected, and then the timestamps of subsequent sampling points are calculated and bound to the sampling results; Step f: the distribution automation terminal generates a waveform recording file using the timestamp marked at each sampling point.

2. The method for synchronous sampling of distribution automation terminals using satellite timing according to claim 1 is characterized in that: In step a, the sampling system includes a main control module, an analog-to-digital conversion module, a mutual inductor and a satellite receiving module. A satellite receiving antenna is installed on the satellite receiving module. The output end of the satellite receiving module is connected to the input end of the main control module. The main control module is bidirectionally connected to the analog-to-digital conversion module. The primary side of the mutual inductor is connected to the power grid, and the secondary side of the mutual inductor is connected to the analog signal input port of the analog-to-digital conversion module.

3. The method for synchronous sampling of distribution automation terminals using satellite timing according to claim 1 is characterized in that: In step c, the actual sampling interval T is calculated as: T = N / Fs, Among them, Fs is the timer operating frequency, and N is the actual configured timer overflow upper limit: N = Round (Fs / (f*np)), Wherein, f is the grid frequency, the sampling frequency is np points per cycle, and Round() indicates rounding operation.

4. The method for synchronous sampling of distribution automation terminals using satellite timing according to claim 1 is characterized in that: In step e, the PPS adjacent sampling point is defined as the PPS sampling point closest to the PPS interruption. When the PPS interruption moment is less than or equal to half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the current sampling point; when the PPS interruption moment is more than half of the sampling period from the current sampling trigger moment, the PPS adjacent sampling point is the next sampling point of the current sampling point.

5. The method for synchronous sampling of distribution automation terminals using satellite timing according to claim 4 is characterized in that: In step e, the time stamp of the second pulse near the sampling point is calculated as follows: When the adjacent sampling point is the next sampling point, the calculation formula of the PPS adjacent sampling point timestamp Sp is: Sp = Tpps + (N-Np) * T ， At this time, wait for the next sampling to end, and after the analog-to-digital conversion module completes the analog-to-digital conversion, bind this timestamp to the sampling result; When the adjacent sampling point is the current sampling point, the calculation formula of the PPS adjacent sampling point timestamp Sp is: Sp = Tpps-Np*T, At this time, wait for the current sampling point to end and bind this timestamp to the sampling result; Among them, Sp is the timestamp of the PPS adjacent sampling point, TPPS is the time information represented by this PPS, N is the actual configured timer overflow upper limit, Np is the timer count of the PPS interrupt record, and T is the actual sampling interval.

6. The method for synchronous sampling of distribution automation terminals using satellite timing according to claim 5 is characterized in that: In step e, the calculation formula of the subsequent sampling point timestamp is: S = Sp + n * T; Where n is the count of subsequent sampling points starting from the PPS adjacent sampling point, T is the actual sampling interval, and Sp is the timestamp of the PPS adjacent sampling point.

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