DE102008044915A1 - Remote reading of smart electricity meters recognizes the phase relationship between local and spatially overlaid reference phases - Google Patents

Abstract

For recognition of the phase relationship between a local reference phase at an electricity meter, being scanned remotely, and an overlaid spatially remote reference phase, with an initial reading of the consumption the data transfer unit is set to detect the difference of a timer at two meters. In a second reading, the meter is set to detect the time reference between the meter timer and the local reference phase at the point of consumption. At least one of the readings is transferred to an evaluation point for a decision whether, for the readings, the local reference phases match or whether another phase relationship is valid.

Description

The The present invention relates to the identification of a local Reference phase of a point of consumption in a multi-phase power distribution network.

electrical Power distribution grids use mostly alternating current and are often multi-phase, in particular three-phase executed. The electrical energy is ideally transmitted via three outer conductors, which imprinted a sinusoidal voltage curve which is phase-shifted by a defined temporal reference is. Usually, both the outer conductors, as well as the temporal relationship of their impressed voltage curves referred to as phase. This ambiguity of the term phase is assumed below, since it is familiar to the person skilled in the art, and thus no obstacle to understanding. Three-phase alternating current has numerous energy transport Benefits, especially low transmission losses. This is a possible symmetrical loading of the phases advantageous. This is trivial to achieve if all consumption points three-phase are connected and the phases evenly strain. In reality, an unbalanced power consumption However, the rule, where often consumption points are connected only single phase. A power company (RU) sets itself the task, a plurality of points of consumption with unbalanced power consumption so to the supply network to join, that in the sum approximate symmetrical load of the supply network results. Is made difficult this task in that the load conditions the consumption points in the course of a day, as well as in the course of Change years. The most important special case of the Three-phase execution is here deepened, although itself the inventive method easily on energy distribution grids with a different number of phases leaves.

modern Electricity meters are capable of removing energy at points of consumption separated into phases separately. The reference phase at a point of consumption is typically included the installation of the electricity meter.

Corresponding becomes physical in the single-phase connection of a point of consumption Defines which phase is taken from there power. The consistent proper assignment of the phases requires considerable effort for Marking and administration. To this assignment even with faulty or to detect missing marking subsequently are measuring methods been proposed, with the help of dedicated measuring a Assignment of the phases over longer distances away. There are known solutions where two spatially remote gauges each be associated with a phase to the temporal relation of to determine comparative phases. There were different Means for synchronization of measurements, for transmission of reference signals or for transmission of measurement results proposed.

Transmission of a reference signal with modems and telephone line ( US 4,626,622 ) Synchronization via GPS signal, transmission with further communication channel ( US 6,130,531 ). Synchronization via GPS signal, transmission of measurement results to paper on foot ( US 7,031,859 ), see also JP002000162258AA ,

At the funds listed here are quite substantial Requirements made.

This goes hand in hand with elaborate work processes. So will in US 7,031,859 described that a worker goes to the on-site measurement, exchanges measurement results with a dispatcher, and then re-assigns individual leads to the available phases based on information received from a dispatcher in a sub-distribution.

• • Es werden dezidierte, im wesentlichen nur für die genannte Aufgabenstellung nützliche Messmittel sowie Kommunikationseinrichtungen benötigt.
• • Es wird an diesen Messmitteln geschultes Personal benötigt.
• • Die messtechnische Zuordnung jeder Verbrauchsstelle ist kaum realisierbar und auch nicht vorgesehen, lediglich komplette Leitungsabschnitte und damit Gruppen von Verbrauchsstellen können überprüft werden.
• • Die erzielbaren Ergebnisse sind vorab kaum planbar, da erst durch die Messung vor Ort erkennbar wird, ob sich wesentliche Verbesserungen bereits durch Änderungen von Zuordnungen in einer Unterverteilung erzielen lassen werden, oder ob beispielsweise an einer einzigen Leitung angeschlossene Verbrauchsstellen auf mehrere, ggf. neu zu verlegende Leitungen aufgeteilt werden müssen.
• • Von Stromunterbrechungen zwecks Änderungen in Unterverteilungen betroffene Verbraucher können nur dann gezielt vorab informiert werden, wenn Messungen und Änderungen in zeitlichem Abstand erfolgen, wofür zwei Arbeitseinsätze vor Ort erforderlich würden.

Thus, the state of the art is characterized by the following disadvantages:

• • There is a need for dedicated measuring equipment and communication equipment which are essentially only useful for the task mentioned above.
• • Personnel trained in these measuring instruments are required.
• • The metrological assignment of each consumption point is hardly feasible and not provided, only complete line sections and thus groups of points of consumption can be checked.
• • The achievable results are difficult to plan beforehand, as it is only on site that it becomes clear whether significant improvements can already be achieved by changing allocations in a subdistribution, or if, for example, new consumption points connected to a single line to be laid lines must be divided.
• • Consumers affected by power interruptions for subdistribution changes can only be informed in advance if measurements and changes are made at intervals, requiring two on-site work.

task The invention is to remedy these disadvantages.

According to the invention, this object is achieved a method having the features of claim 1, using a remotely read electricity meter having the features of subclaims 10 or 11

At Place of dedicated, only for the task mentioned Useful measuring equipment will be cost-effective improvements remote metered electricity meter proposed. Remote electricity meters are known already available today, ie without the invention Advantages, economically advantageous. With her invention Continuing education will open the opportunity to local reference phase of each consumption point metrologically the corresponding parent Assign reference phase. This is an automated procedure proposed, without specially trained staff, and in particular without any staff on site. With that you can possibly necessary work assignments for change the structure of an energy distribution network in the long term centrally be planned, and affected consumers can be timely be informed.

On the basis of the commissioning of a plurality of electricity meters, the method according to the invention is explained by way of example. In a transformer station that supplies a plurality of points of consumption, a data concentrator is installed, which is connected via a wide area network, WAN for short, to the administrative center of an RU. Furthermore, a first meter is installed, which records separately the quantities of electricity fed into the 3 phases by the substation. A highlighted reference phase of the first counter is connected to a highlighted local reference phase of the transformer station. This reference phase of the transformer station is already known. If appropriate, it may have been determined at a higher level by an analogous implementation of the method according to the invention, or it may also be set arbitrarily. The data concentrator cyclically sends a data telegram with a data transmission device, which expresses a request to log in to a network. The first counter has a similar data transmission device and receives with it the said data telegram, identifies itself to the data concentrator by sending out a response telegram etc. Such processes for network formation are known and well researched. As an example DE102004062157A1 , Of course, methods can also be used in which the network formation is initiated by the subscriber to be registered.

One second inventive electricity meter is installed at a point of consumption. The data concentrator unchanged sends cyclic data telegrams, which is a request to sign in to a network. The second electricity meter logs on to the network as previously described. The phase relationship of the second electricity meter for the reference phase the first electricity meter is first unknown and to clarify. The data concentrator sends this a data telegram, which serves as a start signal for the phase measurement, and is received by the electricity meters. The electricity meters start to receive this Data telegram to measure the elapsed time until the next The following positive zero crossing of their respective reference phase elapses. she send a numerical value back to the data concentrator, who represents this time. The data concentrator compares these two times. Agree, then vote the reference phases of the electricity meter match. Is the measured from the second electricity meter Time by 7 ms larger / smaller then rushes its reference phase compared to that of the first counter by 120 ° to / before (Example for a mains frequency of 50 Hz). The data concentrator stores the result of this comparison in an appropriate form. The required precision in timing is by no means to fulfill trivially. This is especially true if Counters with voltage transformers are used by Assembly errors can be reversed, and thus a phase error of 180 °. In this case, need u. U. the phase differences 60 °, 120 °, 180 °, 240 °, 300 ° and 360 °, which equals time differences that are multiples of 3.33 ms (at a mains frequency of 50 Hz), or multiples of 2.78 ms are (at a mains frequency of 60 Hz). For a secure assignment the time differences are expediently so accurately determines that the measurement uncertainty is half of 2.78 ms does not exceed.

On the measurement uncertainty has the transit times of the signal in the medium and differences due to differences Distances from data concentrator to electricity meters none significant influence. At typical distances from below 1 KM is the runtime under 10 microseconds. critical for the measuring accuracy is the favorable design the transmitter-side signal processing. For this it is important that the data telegram, which serves as a start signal for the phase measurement, in both electricity meters down to a maximum Deviation of about 1 ms simultaneously received and evaluated becomes. This can be done by using a suitable ASIC with circuits for receiving data telegrams and timing circuits be achieved. The timing circuits include a Capture register, in which the content of a free-running timer as Timestamp is copied as soon as a data telegram is received. The resolution of the timer and thus the timestamp has while a resolution of well below 1 ms.

Of the same purpose can also be achieved by using a microcontroller with peripheral circuits for receiving data telegrams and can be achieved with peripheral circuits for timing. there the data reception can trigger an interrupt of the microcontroller, during its treatment, a time stamp was taken from a free-running timer becomes. For this purpose, the interrupt latencies are to be kept correspondingly short, which is achieved by suitable program code.

As soon as the voltage curve of the reference phase then a positive zero crossing that is, the sign of the voltage changes from - to +, a second timestamp is generated accordingly. The difference this timestamp corresponds to the time you are looking for.

to Increasing the accuracy can be described in the phase measurement be repeated several times, with implausible results deleted and the remaining will be averaged.

Farther the accuracy of the phase measurement can be increased by a digital filtering of the respective reference phase before the determination the positive zero crossing. After the third electricity meter logged in the network, in the same way its phase relationship to the reference phase of the first electricity meter clarified, and so on. The simultaneous phase measurement on several newly registered electricity meters is possible analogously.

Becomes an electricity meter registered in the network, which is no longer within range of the data concentrator, then becomes an already registered electricity meter in Range of the newly registered counter the previously described Take over role of the data concentrator, so for example send the data telegram as the start signal for the phase measurement serves.

The embodiment described so far links in an illustrative manner a temporal synchronization of two electricity meters with the measurement of the zero crossing of their respective reference phase. In a preferred embodiment, the synchronization of two electricity meters and the measurement of the zero crossing of their respective reference phase separate operations. This is advantageous, since in each case known methods can be used. For the newer field of synchronization in a network, the contribution is exemplified "Time Synchronization" by Marcel Busse, Thilo Streichert ( Algorithms for Sensor and Ad Hoc Networks, Eds .: D. Wagner and R. Wattenhofer, LNCS 4621, pp. 359-380, Springer-Verlag Berlin Heidelberg, 2007 In a first step, the internal clocks of the counters are synchronized. As a result of this process, for example, each of the counters involved can store the path difference of an internal time measuring device with respect to the time measuring device of a reference counter as a numerical value. As a reference counter is a counter with a known phase relationship to the parent reference phase, so for example, the first mentioned counter. The reference counter then determines the time of a positive zero crossing of the parent reference phase, and then sends a data telegram that expresses this time in numerical form. Then, the counters with unknown phase relationship to the parent reference phase determine the time of a positive zero crossing of their local reference phase, where they offset the path difference to the reference counter. Then they subtract the time of the zero crossings of the local and superordinate reference phase from each other, and determine therefrom, as described above, the sought phase relationship.

In A preferred development provide electricity meter and communication unit are separate devices. These have each own time measuring devices with initially unknown retardation on. In this case, the synchronization includes two electricity meters respectively the steps synchronization of the electricity meters with the respectively connected communication unit, and then the synchronization of the communication units with each other. This can also be extended analogously to the case that multiple electricity meters with a single Communication unit are connected.

In a development is the zero crossing of the reference voltage determined by the intended remote communication unit. This is especially true for communication units for powerline communication (PLC) of interest, since these are already for the reception of Data telegrams evaluate the voltage curve of the mains voltage.

In a preferred development, the electricity meters also transmit the assignment of the consumption values to the superordinate reference phase in the context of the cyclical query of consumption values. As a result, the data concentrator sums the quantities of electricity taken at the various consumption points at defined time intervals separately in phases, and compares them with the quantity of electricity respectively fed in at the transformer station determined by the first meter. In the case of a deviation that indicates a technical defect or a manipulation, an alarm is triggered. The phase-separated evaluation significantly improves the achievable in this comparison sensitivity. The separated Evaluation can be achieved automatically with the method according to the invention, without the need for a manual configuration.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• US 4626622 [0005]
• US 6130531 [0005]
• - US 7031859 [0005, 0007]
• - JP 002000162258 AA [0005]
• - DE 102004062157 A1 [0012]

Cited non-patent literature

• - "Time Synchronization" by Marcel Busse, Thilo Streichert [0020]
• - Algorithms for Sensor and Ad Hoc Networks, Eds .: D. Wagner and R. Wattenhofer, LNCS 4621, pp. 359-380, Springer-Verlag Berlin Heidelberg, 2007 [0020]

Claims (15)

A method of detecting the phase relationship between a local reference phase of a remote consuming electricity meter equipped consumption point and a higher, spatially distant reference phase, characterized in that in a first measurement provided for remote reading of electricity quantities data transmission device is used to determine the path difference of a time measuring device of two electricity meters and that in a second measurement, the measuring means of the electricity meters are used to determine the respective temporal relation between the time measuring means of the electricity meter and the respective local reference phase of the respective consumption point that at least one of the obtained measurement results is transmitted via the said data transmission device to an evaluation point, the one has suitable decision maker who decides on the basis of the measurement results mentioned whether the local Bezu or in which other phase relationship they may be. Method according to claim 1, characterized that the first measurement before or after the second measurement, or simultaneously with this expires. Method according to claim 1 or 2, characterized that the first measurement and / or the second measurement each from a Variety of individual measurements. Method according to one of claims 1 to 3, characterized in that the time measuring means of an electricity meter is coupled with its reference phase (network management) and the second measurement with this meter as part of the grid control is carried out. Method according to one of claims 1 to 4, characterized in that it is part of a method for logical networking remotely read electricity meter is, and for each newly logged in a logical network counter identifies its reference phase. Method according to one of claims 1 to 5, characterized in that the reference phases cyclically and / or after power outages. Method according to one of claims 1 to 6, characterized in that the data by said data transmission means be transmitted via cable or wirelessly. Method according to one of claims 1 to 7 characterized in that one for a variety of Applications open transmission channel is used, its transmission characteristics for the transmission of a reference signal would be insufficient. Method according to one of claims 1 to 7 characterized in that in a first measurement of the path difference the internal clocks of two electricity meters is determined by their retardation to the internal clock of a another device, such as a data concentrator, is determined, and these differences in track offset each other become. Remote metered electricity meter equipped for a method of detecting the phase relationship Consumption points according to claim 1, characterized in that He uses a first measurement to measure the path difference between an internal measurement Clock and the internal clock of a second electricity meter determined and that in a second measurement with the for the counting of electricity provided measuring means the temporal relation between an internal clock and the local one Determined reference phase, and that he overcomes the results thus obtained a data transmission device provided for remote reading transfers to an evaluation point. Remote metered electricity meter equipped for a method of detecting the phase relationship Consumption points according to claim 1, characterized in that He uses a first measurement to measure the path difference between an internal measurement Clock and the internal clock of a second electricity meter determined and that in a second measurement with the for the counting of electricity provided measuring means the temporal relation between an internal clock and the local one Reference phase determines that it has measured results over a for the remote reading provided data transmission device receives from a second electricity meter, and that it has an evaluation point that the measured and received values, and the phase relationship of the local reference phases both electricity meters determined. Remote metered electricity meter according to one of claims 10 or 11, characterized that it has a time measuring device whose dimensional standard is in the form of a quartz crystal. Remote metered electricity meter according to one of claims 10 to 12, characterized that it has a time measuring device, which over the Voltage signal of an outer conductor is synchronized. Remote metered electricity meter according to one of claims 10 to 13, characterized that he is from an electricity meter with a remote Communication unit exists. Remote metered electricity meter according to one of claims 10 to 13 by one-piece Production type marked.