WO2016071083A1

WO2016071083A1 - Method for storage and selection of data

Info

Publication number: WO2016071083A1
Application number: PCT/EP2015/073643
Authority: WO
Inventors: Ralf MOSSHAMMER; Yaroslav BARSUKOV; Tobias GAWRON-DEUTSCH
Original assignee: Siemens Ag Österreich
Priority date: 2014-11-06
Filing date: 2015-10-13
Publication date: 2016-05-12
Also published as: AT516425A2

Abstract

The invention relates to a method for the storage and selection of data (5) from a data memory in which data (5) from a plurality of data sources is present in a decentralised system architecture, for example in a low voltage network, which data is stored in at least one record (1) according to a temporal sequence (3) and is retrieved by means of a user request. In order to ensure rapid and reliable database access, the records (1) are stored in rows (2, 9, 10, 11, 12), each row being associated with a data source, according to the temporal sequence (3) and successive row sections (2a, 2b, 2c, 9a, 9b, 9c, 10a, 11a, 11b, 12b), which cover predetermined time sections, are combined to form data blocks (6, 7, 8), wherein the method for the selection of data (5) upon a user request comprises the following steps: - selection of the data blocks (7, 8) which cover the searched region (4); - analysis of data (5) lying in the row sections (2b, 2c, 9b, 9c, 11b, 12b) in the data blocks (7, 8); - selection of the row sections (2b, 2c, 9b, 9c, 11b, 12b) which contain data (5).

Description

description

Method for storing and selecting data

FIELD OF THE INVENTION

The present invention relates to a method for

Save and select data from one

Data memory in which data from multiple data sources in a decentralized system architecture, for example in a low-voltage network, are present, which are stored at least in a data set according to a time sequence and are queried by means of a user request.

Such data sources, which may also be referred to as network nodes or data points, may be: power generators (e.g., photovoltaic systems, small wind turbines) or their

Actuators (e.g., transducers), flexible consumers (e.g.

electric storage heaters, buildings with and without

Building automation system) and corresponding actuators,

Transformers, measuring devices such as smart meters and in particular so-called intelligent electronic devices (intelligent electronic devices), such as processor-controlled regulators of

Circuit breakers or transformers.

Data within the meaning of the invention may be: measured values for electrical current, measured values for electrical voltage, measured values for electrical power, time of the measurement, as well as metadata relating to the transmission, eg number of nodes passed, latency (delay time). STATE OF THE ART

Local intelligent control schemes distributed over a low-voltage grid are gaining more and more importance in the architecture of intelligent networks. A basic requirement for automatic monitoring and control is a solid basis of measuring equipment, for example in the form of "smart meters" (intelligent meters), intelligent inverters or intelligent building services.

While immediate values or information are crucial for short-term control measures, a stable regime would also consider historical values and incorporate them into medium- or long-term planning. Historical data can be used in a central database not only for current and voltage regulation, but also for short-term correction in case of data loss, and facilitate various planning.

Such a central database is using a

Analysis method and a data management system, such an approach having a decentralized system architecture, such as a low-voltage network, several disadvantages:

The data from a low level of the system architecture (e.g., intelligent electronic equipment (IED)) must be transported at the highest possible data rate to the top level of the system architecture (e.g., the central database), where

High-speed connections, for example in the form of broadband connections, must be used. However, these high-speed connections can only be done with a small number of node connections, such as For example, in an intelligent building services

is present. With a large number of node connections, a high latency and a low bandwidth set, whereby a small

Data transmission over the power grid, the so-called "Distribution Line Communication" (DLC), is the result.

- The data center or the central control and control logic represents a danger point for potential errors, the default probability and the

associated costs are a significant issue. Data centers are usually redundant several times, so that the probability of failure is very low, but not negligible. The cost of a total loss, however, are large, which is why a decentralized and

inexpensive backup solution should be used.

- The actuators in low-voltage networks are usually arranged in the network itself, that is, either on the secondary side, for example in the form of a

Transformer, or in the network itself, e.g. when

programmable inverter, are distributed. This means that in a centralized system

Decisions regarding a network level at the

Automation level. This results in an error point in the data connection between these layers, even if the data center itself is multiply redundant.

- The dataset of a central instance, which is a

Variety of low voltage network nodes is enormous compared to medium or high voltage networks. It is expected that in normal operating condition suitable Algorithms can control such a flood of data, with unpredictable conditions or events should be handled by a human for legal or security reasons.

Due to these problems, it is recommended to install at least one basic backup solution for local remote operation (in the respective low-voltage grid). Or to provide the local operators with a local database based on historical measurement data so that such a problem can be inexpensively overcome by the operator.

There is currently no universal commercial

available solution for the control and monitoring of local low-voltage networks. An uncomplicated technical solution would be either a volatile memory or a memory

Database implement, both solutions have disadvantages.

The use of a volatile memory, such as a RAM memory, to secure measurement data in a device has the advantage that very fast access times compared to a permanent memory are possible, but the risk of data loss is enormous. It is known that a planned or unscheduled restart of the device can lead to a complete loss of data,

for example, a short-term loss of power.

In addition, the maximum possible data volume is one

Volatile memory is usually much lower than that of a so-called read-only memory (ROM memory, i.

Hard drives, flash drives, EEPROMs, etc.), due to the high cost of these preferably embedded or

Compact devices are applied. With the help of a database, the problem of data immunity is usually avoided and it can

different requesting mechanisms are created, however, databases due to technical

Requirements, such as one

Transmission security, a risk in many IT applications represent. In this regard, high performance databases are a known solution, but at a high cost.

Although databases are usually two-dimensional, usually only the vertical dimension

(Columns) dynamically while the horizontal dimension

(Lines) is statically formed. Of course they can

Rows and columns are also designed to be dynamic and static in the opposite way. In general, however, this division into a dynamic and a static area presents a significant space problem since databases are best suited for storing dense data and a two-dimensional table for large volumes of data

usually too small.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a method by which specific data entries in

simple way and with low access and

Transmission times can be read out. In other words, it is an object of the invention to provide a database construction and a data storage architecture and an associated method, whereby a reliable rapid data access is ensured. This particular for data

Low voltage networks coming from different data sources different time intervals in the data memory

arrive.

This object is achieved by a method according to claim 1, by storing the data records in rows, which are each assigned to a data source, according to the time sequence and successive

Line segments that cover predetermined time segments are combined into data blocks, wherein the method for selecting data in a user request comprises the following steps:

- Selection of those data blocks that contain the searched area

cover;

- analysis of data lying in the row sections in the data blocks;

- Selection of those line segments containing data.

An inventive data set thus consists of several lines and contains for each data source at least one line. In one line, all data are entered after the time of their measurement, whereby the position of the respective data in the line corresponds to a certain point in time. Thus, for example, the line could be subdivided into many time units, in particular the same length, the data being allocated to a specific time unit. Time units of a line where there is no data of the corresponding data source remain free.

The lines are now subdivided into line sections that correspond to a given period of time (that is, contain a certain number of time units), which is the same for all lines. All line sections of a given period of time result in a data block, also called

Can be called "time strip." Contains a data block So the data of all data sources in a given

Period.

Now a user request is made for certain

Data sources the data for a desired period of time

read out first those data blocks

("Time strips") are selected to cover the desired period of time, then it is analyzed which line sections are data, and then these line sections

selected.

The data structure consists of rows and columns, the columns correspond to specific time periods,

while the lines are different data sources,

For example, network nodes correspond. The length of the lines will increase with time and is not limited to the

Number of lines and thus the length of the columns are fixed.

In other words, the user queries a particular area within the temporal sequence, with those

Line sections are detected which are within the sought range. Following are the

Detected line segments analyzed in more detail, which is determined which line sections actually contain data. Thereafter, the data information of the data-containing line segments are provided to the user.

This row and column structure is present both in the lower level of the data memory or in a RAM where the most recent data is stored, as well as in the persistent memory or upper level of the data memory. In addition, the present application discloses a two-stage data memory for a decentralized

System architecture, for example in the form of a

Low-voltage network, for the selection of at least arranged in a record data. In detail are the

Data records in rows, which are each associated with a data source, stored according to the time sequence and successive line segments covering predetermined periods, combined into data blocks, wherein the data structure is formed at least two stages by a first stage as volatile memory contains younger data, while a second stage as permanent storage contains older data than the first stage.

In other words, it is a two-tiered data storage architecture, with the first (lower) tier providing general mechanisms for storing arbitrary data and unifying the advantages of an internal memory ("cache") and a durable database solution any division of a physical

Data storage between different types of storage. These are: volatile memory (eg RAM memory etc.),

Permanent memory (eg ROM, HDD, flash memory, etc.) and network nodes with local memories, which are, for example, local computer architectures with

Storage drives act.

The second layer of the memory architecture represents a project-specific data specialization, which

allows a query of data in the database is possible. From the combination of the method according to the invention with the two-stage data memory, there is the advantage that the otherwise usually high storage duration and the

Processing time much more efficient from the

inventive system architecture and the associated

Procedures are carried out so that an efficient

Data storage is guaranteed. It is also in

Depending on the application a kind of

permanent data storage, otherwise historical values would be lost and only the most recent values could be delivered, but this is inadequate for a modern, service-controlled voltage network with stable regulation.

It is possible that the sequence for storing in constant steps in the form of a timeline is performed. This has the advantage that each data entry or all data at a particular time or a specific

Step, whereby a rapid query according to the above-described method can be performed.

In a further embodiment of the invention, a determination of the number of in the

Line data existing data carried out. This essentially serves to quickly respond to a user request

determine how large the amount of data the user has selected and wants to download.

In a further embodiment of the invention, the download of data is selected from the selected ones

Line sections limited to a maximum number. This is to prevent user requests that cause excessive data traffic and other important processes in the data store or in the communication network decentralized system architecture, such as collecting the data in the data store.

It may also be a query of the data of the line sections are performed, in which query the data to another location in the decentralized system architecture

be transmitted.

The method may also be designed to analyze latencies (in the transmission of the data to the data memory) or even data failures based on statistics when querying the line segments, thereby

Statements about the behavior of the communication network can be made.

The described architecture is thus suitable for storing measured values in a time sequence, which also makes the method flexible with respect to an actual data implementation. The two-stage concept

allows the architecture in a variety of ways

Use applications quickly.

The availability of historical data at a secondary level enables novel applications, such as network-based historical graph monitoring and monitoring systems, allowing network operators a precise sense of the current network status, such as a low voltage network.

To that end, algorithms that are provided with historical data could immediately enable network operation without having to gather information at the beginning for some time to get an idea of the current network condition. In this case, a statistical analysis of the data provide insight into the network structure and the system architecture, where, for example, a correlation analysis of the voltage levels gives a rough impression of the network layout or the topology. Complex algorithms such as neural networks can use historical data for training.

In an embodiment according to the invention, it is provided that a frequency distribution and / or an arrival time of the data record is stored for each of the data blocks. That is, it is determined in which temporal

Intervals the data arrive at the data storage, from which then, as already mentioned above, even faster latencies or data loss of the communication network can be determined.

In summary, the processing of user requests is significantly accelerated by the inventive method, since the area to be examined within the specified

Process is significantly restricted.

It should be emphasized that the

Two-stage data memory according to the invention and the associated method for reading out the data not only for

Voltage networks, but for any decentralized

System architectures is appropriate because of the respective

respond flexibly to specific requests without causing large data transfers.

BRIEF DESCRIPTION OF THE FIGURES

To further explain the invention, reference is made in the following part of the description to the figure, from the further advantageous embodiments, details and

Developments of the invention can be seen. It shows

Fig. 1 is a schematic representation of the basic

according to the invention two-dimensional

Database construction.

WAYS FOR CARRYING OUT THE INVENTION

Fig. 1 shows a schematic representation of a

in principle two-dimensional data set 1 according to the invention, wherein a time sequence 3 from t = 0 to t = 20 in the upper region is indicated continuously. Each of the values from 0 to 20 corresponds to a time unit, the time units are the same size. The time units from 0 to 6 are summarized at a predetermined period corresponding to the data block 6, the time units from 7 to 12 are combined at a predetermined period corresponding to the data block 7, and the time units from 13 to 20 are combined at a predetermined time that the

Data block 8 corresponds. The periods, which the

Data blocks 6-8 are equal in length. Several

exemplary data sources (data points) A, Bx, By, Bz, C are given in the form of lines 2,9,10,11,12 with each other. Thus, the time sequence 3 is a kind

vertical column division, while horizontally extending lines 2,9,10,11,12 represent a kind of line division, the column division to another

Breakdown is divided into data blocks 6,7,8, which is concerned with the lines 2,9,10,11,12 in the field of

Line sections 2a, 2b, 2c, 9a, 9b, 9c, 10a, 1 la, 1 lb, 12b cut. A request made by a user for a "data point B *" (that is to say all data points beginning with "B") in a range 4 from t = 10 to t = 17 is carried out in this database, which is split into data blocks 6, 7, 8 only the two lines 9 and 11, that is to say the data points Bx and Bz, within the data blocks 7 and 8, since the data point By or the line segments 10b and 10c contain no data 5. It should be noted that "B *" includes all "B" data points, ie Bx, By and Bz.

Here, for each line 2,9,10,11,12 or for each

Line section 2a, 2b, 2c, 9a, 9b, 9c, 10a, 1 la, 1 lb, 12b a

Frequency distribution of the requests and / or an associated time of arrival are stored, whereby also the duration of the data transmission is recorded, which serves two purposes:

1. For certain data 5, the frequency measurements can be exported to provide useful statistics about the

Behavior of the underlying data transmission network, for example with respect to the latencies,

Power failures, etc.

2. If a request accesses the data set 1, the frequencies of the requested data blocks 7,8 can be compared with respect to the affected data 5 and its lines 2,9,11,12 and

Line sections 2a, 2b, 2c, 9a, 9b, 9c, 10a, 1 la, 1 lb, 12b are used to rapidly generate an estimate of the data sets. This could, for example, also serve to suppress very large inquiries by which the

Net connection would be unnecessarily overloaded.

List of reference numbers: 1 record;

2.9 ... 12 lines;

2a ... 2c line sections of line 2;

3 temporal sequence;

4 area to be examined;

5 requested data (e.g., from a data point B *); 6 ... 8 data blocks;

9a ... 9c line segments of line 9;

10a line portion of the line 10;

IIa ... IIb line sections of line 11;

12b line portion of the line 12;

A, Bx, By, Bz, C Data sources (data points)).

Claims

claims

1. A method for storing and selecting data (5) from a data memory in which data (5) from

multiple data sources in a decentralized

System architecture, for example in one

Low-voltage network, present, which at least in a data set (1) according to a time sequence (3)

are stored and queried by means of a user request, characterized in that the

Data records (1) in lines (2,9,10,11,12), which are each assigned to a data source, are stored according to the time sequence (3) and successive line sections (2a, 2b, 2c, 9a, 9b, 9c, 10a, IIa, IIb, 12b) covering predetermined periods of time are combined into data blocks (6, 7, 8), the method of selecting data (5) upon user request

subsequent steps include:

- Selection of the data blocks (7, 8) that contain the searched

Cover area (4);

- Analysis of in the line sections

(2b, 2c, 9b, 9c, IIb, 12b) in the data blocks (7,8)

data (5);

- Selection of those line segments (2b, 2c, 9b, 9c, IIb, 12b) containing data (5).

2. The method according to claim 1, characterized in that the time sequence (3) for storing in constant steps in the form of a timeline is performed.

3. The method according to claim 1 or 2, characterized in that in the analysis, a determination of the number of in the line sections (2b, 2c, 9b, 9c, IIb, 12b) existing data (5) is performed.

4. The method according to any one of the preceding claims, characterized in that the downloading of the data (5) from the selected line sections (2b, 2c, 9b, 9c, IIb, 12b) is limited to a maximum number.

5. The method according to any one of claims 1 to 4, characterized

characterized in that latency times based on statistics when querying the line segments

(2b, 2c, 9b, 9c, IIb, 12b).

6. The method according to any one of claims 1 to 4, characterized

characterized in that data loss based on statistics when querying the line segments

(2b, 2c, 9b, 9c, IIb, 12b).

7. The method according to any one of the preceding claims, characterized in that a frequency distribution of the data record is stored for each of the data blocks (6,7,8).

8. The method according to any one of the preceding claims, characterized in that an arrival time of the data record is stored for each of the data blocks (6,7,8).

9. The method according to any one of the preceding claims, characterized in that a query of the data (5) of

Line sections (2b, 2c, 9b, 9c, IIb, 12b) is carried out, in which query the data (5) are transmitted to another location in the decentralized system architecture.

10. Two-tier data store for a decentralized

System architecture, for example in the form of a

Low-voltage network, for selecting at least in a data set (1) arranged data (5) according to a method according to one of claims 1 to 9, characterized in that the data sets (1) in lines (2,9,10,11,12), which are each assigned to a data source, according to the time sequence (3) are stored and

consecutive line sections

(2a, 2b, 2c, 9a, 9b, 9c, 10a, IIa, IIb, 12b) covering predetermined periods of time to data blocks (6,7,8)

are summarized, wherein the data structure is formed at least two stages, by a first stage as a volatile memory contains younger data (5), while a second stage as a permanent memory older data

(5) as the first stage contains.