RU2658264C1 - Method of periodical collection of digital data in the distribution measurement systems through low-speed channels of communication with high level of interference - Google Patents

Abstract

FIELD: computer engineering.

SUBSTANCE: invention relates to computer engineering. For this, heterogeneous data are combined in the form of queries and responses into the information packets, grouping them in such a way, that in view of the previously known list of measured values, the data on which should be collected during the given period and the forecast of the total time of the task execution based on the time of successful collection sessions, the number of packets was minimal with the maximum possible filling of the modem's sender buffer, which is connected to the communication channel; the requested values are transferred consecutively without additional overhead information in the order, which is defined by the query, where for the data, the size of which is not known, the mechanism for the additional request for data, which are not included in the package, is engaged, the mechanism contains the response to the previous request; polling of various devices between the information collection assembly is redistributed based on, in the decreasing order, the characteristics of the operability of the route for the recent time.

EFFECT: technical result is the reduced data acquisition time, the increased number of data sources for polling through the communication channel, and the selection of the stable communication channel out of several channels.

1 cl, 3 dwg

Description

The invention relates to a method for transmitting digital data and can be used to obtain heterogeneous information in distributed measuring systems for collecting information through various low-speed communication channels installed at stationary electric power facilities.

The invention relates to the field of information measuring and computing. The invention can be used to build information exchange processes in distributed measuring systems, including for reading data from electricity meters and measuring devices containing information about power consumption, parameters of the electric network, power quality indicators, the state of metering meters and devices with transmitting information over wired and wireless communication channels with a high level of interference, for example, radio channels, data channels for power Networks (Power Line Communication).

State of the art

Distributed measuring systems are used in many fields and in particular in the electricity sector as the basis of automated systems for commercial metering of electricity and other systems where the use of low-speed communication channels with a high level of interference (radio channel, PLC) allows you to organize communication within one (less often several neighboring) transformer substations (TP) and power lines, or buildings or structures. The data transfer speed depends on the network topology and noise environment, on the level of interference affecting the signal transmission. In the absence of direct communication, repeaters are used. Such communication channels are widely used in information-measuring systems, which exist independently as automated systems for commercial accounting of electricity or are part of intelligent electric power systems with an active adaptive network. In addition, the world electric power industry uses a large number of automated systems that perform the functions of relay protection and emergency control, telemechanics, technical metering of electricity, and registration of emergency situations. But in the used low-speed communication channels in automated systems, bandwidth and a high level of interference are limited, which makes it impossible to ensure reliable periodic data collection from devices.

A known data acquisition system (RF patent No. 2485582), characterized in that several (at least two) different data acquisition tasks can be stored in the memory of the data acquisition module, one of which is selected depending on the state of additional external task selection signals.

The disadvantage of this method is that the system additionally requires the presence of an additional bus and sync bus line, and one of the collection tasks is selected depending on the state of additional external task selection signals, which necessitates the presence of external signals and complicates the system.

For the closest analogue, a method of polling data based on blanks of output messages and a list of recipient addresses is adopted (see RF patent for invention No. 2362211).

The method according to the aforementioned patent consists in generating output information on the state of a plurality of input signals in the systems for collecting, converting, transmitting data and control, which consists in periodically polling non-telematical sources of input signals and periodically reading a set of current values of these signals.

A sign of the closest analogue, coinciding with the essential sign of the claimed invention, is the periodic reading of the set of current values of these signals.

The reasons that impede the receipt of a technical result for the above analogue, which is provided by the claimed invention, are as follows. The application of this method is difficult in information-measuring systems because of the need to set in the computer memory an array of instructions, a list of blanks for telematic messages, a list of recipients, for non-telematical threshold values for the absolute value of the difference between the current and previous values. The method involves the use of manual labor for entering information into computer memory, which increases the costs of operating the system associated with the need for a sufficient amount of memory, manually enter information during the initial installation of the system and each time it is upgraded.

A common drawback of approaches to the periodic collection of digital data used in the above patent sources is that it is difficult to transmit heterogeneous information at predetermined periods of time via low-speed communication channels with a high level of interference, and it is also necessary to set predefined information in the computer memory, which is time-consuming process, if necessary, to collect heterogeneous information. The need to use additional signals and lines increases the cost of distributed measurement systems.

Salient features of the claimed invention are algorithms, functions and protocols for periodically collecting digital data data having a heterogeneous structure and content, via low-speed communication channels with a high level of interference, dynamically grouping these data so that the number of packets over a given period of time is minimal, and the transmitting clipboard was maximized, while ensuring continuous monitoring of the level of interference in the communication channel for automatic tuning of parameters soap has data.

The technical result that can be obtained using the proposed method is to reduce the collection time of data accumulated over a certain period, for example, one day, increase the number of data sources that can be interrogated through a communication channel for a certain period, and choose the most stable channel communication of several possible, increasing the accuracy of time management by data sources and its assessment, which leads to the possibility of using communication channels having a high level of omekh, but at the same time inexpensive (radio channel, PLC, etc.), which reduces the cost of building and operating measuring systems in the electric power complex.

SUMMARY OF THE INVENTION

The objective of the invention is the creation and implementation of a method of reducing the time of collecting heterogeneous data accumulated over a certain period, increasing the number of data sources that can be interrogated over a certain predetermined period of time, choosing the most stable communication channel from several possible, increasing the accuracy of time keeping by data sources and her grades.

Brief Description of the Drawings

Consider heterogeneous data accumulated by devices in distributed measuring systems, for example, an electricity meter (PU) over a certain period of time, for example, a day. The devices record electricity values on an accrual basis at the end of every day, power, voltage and current profiles averaged over a specified interval (for example, 15, 30 or 60 minutes), network parameters, event logs and information about the status of the device and the electric network and other types of data which are heterogeneous in structure and format, size, method of measurement and storage.

A distinctive feature of low-speed communication channels with a high level of interference is the high probability of loss or distortion of the transmitted information. In switched communication channels, data transmission is preceded by a connection, the duration of which can significantly exceed the time of direct data transmission. In addition, the amount of data that can be transferred during the connection is limited. Therefore, to reduce the total data collection time, it is necessary to transfer the maximum possible amount of data at each connection setup.

To solve the problem, it is necessary to use such a data transfer protocol that allows you to dynamically group heterogeneous transmitted data accumulated by the device over a period of time in one package. Standard protocols have one degree or another of redundancy, therefore, the claimed method proposes the use of a specialized protocol that has a binary format and uses data compression based on statistical information about the transmitted data.

FIG. 1 shows the structure of an exchange protocol for transmitting heterogeneous data.

The requested values should be transmitted in a row without additional service information in the manner specified by the request. Also, for data whose size is not known in advance (for example, event logs), a mechanism is added for additional data retrieval, which did not fit into the packet containing the response to the first request.

Since the time of collecting data accumulated by a data source for a certain period decreases, the number of data sources that can be interrogated for a certain period increases (1)

where N _ID is the number of data sources, T _ND is the period of data accumulation, t _SD is the data collection time of one data source.

If, due to interference in the communication channel, some type of data accumulated over a certain period (for example, one day) was not received together with other types of data, or more collection speed is required than the data collection period used, such data can be collected through a separate request. It is also necessary to obtain the largest amount of data in one answer. For example, if an electric meter is used as a device and a measuring system, the amount of data in one answer for each measured quantity (active and reactive energy, power, voltage, current, etc.) depends on the number of measured quantities, the data collection period is inversely proportional to the quantity measured values, data for which it is necessary to obtain (2)

where T _SD - the period of data collection, T _ND1P - the period of accumulation of data of one type of measurement, placed in 1 answer, N _IV - the number of measured values.

Since the list of measured values, the data for which it is necessary to collect, is known in advance, the data collection period can be determined based on this list.

Based on the time of successful collection sessions in the course of the task, a forecast is made of the total time of the task (3)

where t _OT is the predicted task execution time, t _OCi is the time of data collection from the i-th counter, N _SU is the number of counters from which data was successfully collected, N _C is the total number of counters.

FIG. 2 depicts the order of starting and changing the priority of a periodic data collection task. The priority of the data collection tasks is selected in accordance with the data collection period. The shorter the data collection period, the higher the priority of the task. If there were failures during the work of the task, the priority of the task is lowered to ensure the work of tasks with lower priority.

The system of periodic collection of digital data continuously monitors the level of interference in the communication channel and, for automatic adjustment of data transmission parameters, calculates the status of exchange efficiency, effective speed, and estimation of task collection time. The exchange efficiency over the communication channel can be determined by the formula (4)

where EO is the exchange efficiency, KO is the number of responses, SC is the number of requests.

The effective exchange rate over the communication channel is determined by the formula (5):

where ESO is the effective exchange rate, RP is the request size, PO is the response size, t _exchange is the time between the end of the response and the start of sending the request.

The communication channel in the proposed method can use a data network, different parts of which are characterized by different signal-to-noise ratios, respectively, for different parts of the network it is possible to use noise-resistant coding with different efficiencies and, as a result, with different transfer rates of useful data.

If the data of one source can be obtained through different routes connecting the network devices directly or through repeaters, then you must select a route based on the following criteria in descending order of importance:

- a characteristic of the health of the route in recent times;

- statistical information about the stability of the route for a certain period;

- measured signal quality in the worst section of the route;

- the number of repeaters.

FIG. 3 depicts the redistribution of a survey of various devices between several nodes for collecting information based on multi-criteria analysis.

Routes can be selected as information on them is updated, and for routes with similar characteristics, it is necessary to use a switching threshold for each calculated parameter.

Since the time of data transmission in a switched communication channel can be non-deterministic, for the functions of transmitting information about the current time to the data source and reading it, channel-forming equipment must ensure the transmission of the duration of the transmission of information to the information recipient.

When transmitting the same information to all nodes of the network, broadcast transmission is used, followed by address control of the success of the transmission and address transmission of the parts not transmitted by broadcast.

Claims (1)

A method of collecting digital data in devices of distributed measuring systems through low-speed communication channels with a high level of interference, which consists in periodically reading this information from devices, characterized in that they combine heterogeneous data in the form of requests and responses into information packets, dynamically grouping them so so that, taking into account the previously known list of measured values, the data for which you need to collect during a given period, and the forecast of the total time of the task based on the time of successful collection sessions, the number of packets was minimal with the maximum possible filling of the transmitting buffer of the modem connected to the communication channel, the requested values are transmitted consecutively without additional service information in the order determined by the request, and for data whose size is not known in advance, the data retrieval mechanism is activated which did not fit in the packet containing the answer to the previous request, continuously monitor the level of interference in the communication channel to automatically fine-tune the parameter in data transmission - speed, frequency, packet size, apply a communication protocol that has a binary format and uses data compression based on statistical information about the transmitted data, accumulate data in compressed compressed archives transmitted over communication channels at those times when the interference level in the communication channel is minimal, redistribute the interrogation of various devices between several nodes for collecting information based on, in decreasing order of importance, the performance characteristics of the route recently I, statistical information about the stability of the route for a certain period, the measured signal quality on the worst route segment, the number of repeaters, is used in conjunction with the information packages of an additional service that provides information delivery time measurement, send broadcast messages to devices with subsequent individual verification and delivery of the missing parts of the information .

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