WO2012110607A1

WO2012110607A1 - Method for functionally analysing electrical loads

Info

Publication number: WO2012110607A1
Application number: PCT/EP2012/052703
Authority: WO
Inventors: Ralf Tanneberger
Original assignee: Ralf Tanneberger
Priority date: 2011-02-16
Filing date: 2012-02-16
Publication date: 2012-08-23

Abstract

The invention relates to a method for functionally analysing electrical loads, in which a pattern of a characteristic parameter, generated by the load, is determined and compared to a desired pattern of the characteristic parameter during a normal state of the load and an alarm signal is generated if there is a significant difference. The aim of the invention is to carry out such a functional analysis with little expenditure. This is solved by virtue of the fact that a pulse train representing the electrical power consumption of a load is generated from a counter in such a manner that the pulse frequency represents the power, and the pattern of the temporal profile of the pulse frequency or the power consumption of the load determined therefrom is compared to a normal pattern and the alarm signal is generated if there is a difference.

Description

Method for functional analysis of electrical consumers

The invention relates to a method for functional analysis of electrical loads, in which one of the

Consumer generated pattern of a characteristic

Parameters is determined. This pattern is compared with a nominal pattern of the characteristic parameter that was determined during a normal state of the consumer

(Normal pattern) compared. At a significant

Deviation of the normal pattern from the target pattern, an alarm signal is generated. It is known to continuously access various devices with respect to patterns of characteristic parameters

in order to derive errors or the need for ongoing maintenance. For example, a vibration analysis or a vibration analysis is a known underpass method of rotating parts that rely on

Errors, such as imbalances or defective bearings can be concluded. Vibration analysis is an element of predictive maintenance. In the vibration analysis, the

Vibrations of rotating parts (e.g., rollers)

recorded and analyzed. On the basis of the vibration patterns and the vibration amplitude conclusions can be drawn on the condition of the rotating parts and the bearings.

As a result, necessary repairs can be identified in advance and carried out before failure of the machine. This can reduce downtime and production-free Times are shifted.

Such functional analyzes are not with one

associated with insignificant technical effort. In particular, there are special sensors on the devices or

Provide facilities and appropriate wiring to these sensors. In addition, the arrangement of such sensors or sensors usually also has an influence on the behavior of the machines and equipment itself. The electrical power that an electrical consumer receives over a unit of time is called electrical energy. The electrical energy that a consumer obtains is determined by a meter. The detection of electrical significant electrical loads in

Industrial equipment is used for system monitoring and cost-oriented post costing today usually only electronic pulse counter.

Such a pulse counter counter has a pulse output at which a current energy reference corresponding pulse number is output. The number of pulses can be set according to the desired resolution. Typically, pulse numbers are between 1 to 10,000 pulses per kWh. Depending on the power consumption of the connected

Consumer can then be set the pulse number, which corresponds to 1 kWh. This is also called pulse value.

At very low power consumption can be a higher

Pulse number are set and with high power consumption, a correspondingly lower to keep the pulse pauses in a meaningful frame for further evaluation, because at the same energy reference the pulse pauses at low pulse value (higher number of pulses per kWh) are shorter than at higher pulse value (lower Number of pulses per kWh)

In the pulse counter is now according to the

set pulse value of the energy consumption of the electrical load by counting the pulses over the measuring time interval determined and displayed. Thus, the energy consumption since the beginning of the measurement can always be displayed on such a counter and evaluated accordingly.

The invention is therefore based on the object, a

Provide functional analysis, which can be carried out with significantly reduced effort and possibly using existing facilities.

The invention is solved by a method having the features of claim 1. The claims 2 to 7 indicate particular embodiments of the method according to the invention.

In the invention, it is assumed that a pulse train is output from a pulse generator counter whose respective current pulse repetition frequency represents the height of each current power reference of a consumer. This is irrelevant to the actual function of a counter, but became a finding in the invention

used .

According to the invention, this realization generates a pulse train representing the instantaneous electrical power consumption of a load. This is done in such a way that the pulse value and thus the pulse frequency power ratio are adjusted so that the

Pulse frequency is always higher than a frequency

periodic load change (load change frequency) on the

Consumer. This makes it possible, during the period of a load change several times the current pulse interval and thus the current pulse frequency and from there again the measure instantaneous power consumption.

A load change frequency determined by those skilled in the rule of the period between two identical or similar recurrent load states. For example, the load change frequency can be determined by the speed of a motor shaft or by the speed of a shaft of the output. For example, but also the time from a charging a melting furnace on the melting and tapping to re-feeding the period of

Represent load changes.

The invention assumes that, for example, the

Occurrence of imbalances on rotating parts always with an increase in power consumption and a serious change in the current power consumption or

Momentanlastamplituden is connected.

Their output frequency is proportional to the instantaneous load of the connected consumers. Each load change therefore has an effect as a pulse frequency change. It is true, the higher the frequency the more accurate statements can be about the

Operation of the connected machines are made

By the now multiple possible during a load change determination of the instantaneous power consumption, it is possible via a corresponding evaluation and storage to record a pattern of the time course of the pulse frequency or the power consumption of the consumer determined therefrom. This pattern can then be combined with a

Normal patterns are compared. If the two patterns deviate from one another by a significant range to be defined, then an alarm signal is generated. The

Normal pattern can be determined and deposited, for example, if the consumer has a demonstrably normal

Behavior shows, for example after a maintenance or a

First commissioning. The normal pattern can also be during be updated, for example by

permissible drifts so that they do not lead to a fault trip.

As an error that lead to an alarm triggering impermissible drift that may arise, for example, by a slowly increasing bearing friction and eventually lead to a triggering a safety switch, can be detected in good time, for example, before

Switch off. But even so-called structural jumps can lead to an alarm triggering, namely, if the recorded pattern suddenly deviates from a pattern defined as a normal pattern, for example in the event of sudden bearing damage.

It has been described above so

characteristic amplitude sequences of the power consumption of

Plants in normal operation. Now announces a fault below the fault threshold (e.g.

Overcurrent protection devices for electric motors)

conventional protective devices is located, and / or visible by structural jumps, so can a connected

Computer system these deviations from one

determine the historical amplitude sequence.

The solution according to the invention thus achieves that counters which are used anyway can be used in front of consumers for the functional analysis without the need for special technical devices. The cost advantages of this solution are obvious.

In one embodiment of the method according to the invention it is provided that the pulse frequency is at least ten times the load change frequency. With such a height of the pulse frequency, so to speak, the sampling rate is set. The higher the pulse frequency, the more accurate the information. Therefore, in another special Design provided that the pulse frequency is ten to thousand times the load change frequency.

In a further embodiment of the invention

provided that the normal pattern from the pattern of

Load change of a previous period is determined. The prerequisite is, of course, that the

Consumers in the previous period has processed in its normal state. This normal state usually brings significant periodic changes in the

Instantaneous load, which in native constantly

recurring burdens have their cause. Now occurs a damage to the consumer, which is a higher

Requires instantaneous power, so differs this load pattern from the current damaged state of the normal pattern and this is to determine the need for a

Alarm signal used.

The pattern can be calculated from the average values of

Power consumption of several previous ones

corresponding time intervals are determined. Such an approach will ensure that any deviations in the current

Load patterns to a representative normal pattern

average out.

Appropriately, in one embodiment of the

According to the invention stored the pattern of load changes and determined from the normal pattern. This arithmetic process can also take place during operation, since the stored load change patterns are indeed in the static state. If then the normal pattern is recalculated, this can replace the previous one

Normal pattern. In this respect, it can be provided in a further embodiment of the invention that the normal pattern is updated from respectively younger gradients of the pattern. By such an update Any load drift at the load can be calibrated out.

Of course, it is possible to change the normal pattern over several load change periods, i. at least two

Load change periods, to take away. This can also be a long-term storage, for example, from the first commissioning of the consumer. To eliminate random errors in the normal pattern determination, it is also possible to assemble the normal pattern from a plurality of patterns that have been recorded over corresponding periods of time, for example via an averaging.

In particular, to support long-term storage, data compression may be appropriate. It is possible to search the normal pattern for significant features, which can also be done over several comparatively pattern. From this, significant data can then be determined. For example, if significant high or low amplitudes occur within a period at the same time locations, it may be sufficient to store only those spectra of maxima or minima as the normal pattern. The comparison pattern then only needs to be searched for this spectrum in order to arrive at a statement about the degree of agreement. The number of data is thus significantly reduced. The invention will be described below with reference to a

Embodiment will be explained in more detail. In the

accompanying drawings shows

Fig. 1 is a representation of the implementation of a measured power consumption of a consumer in a

Pulse repetition frequency;

Fig. 2 is an illustration of a significant course

Load on a consumer over that in Fig. 1st illustrated method in normal operation of the consumer;

FIG. 3 is an illustration of the load bearing pattern on a load in the presence of a fault; FIG.

4 shows a schematic representation of an arrangement for carrying out the method according to the invention;

Fig. 5 is an illustration of a typical inconspicuous

Amplitude sequence of an asynchronous motor with connected feed pump;

Fig. 6 is an illustration of an abnormality in the behavior shown in Fig. 5 by a slowly steady increase, for example, caused by an increasing

Bearing friction;

7 shows a representation of a conspicuousness in the behavior shown in FIG. 5 by a slowly steady increase, for example caused by bearing failure;

8 is an illustration of a conspicuousness in the behavior of an asynchronous motor shown in FIG

connected pump by secondary overheating of the conveyor mechanism; 9 is an illustration of a conspicuousness in the behavior of an asynchronous motor shown in FIG

connected pump due to a resonant vibration due to rapid wear and

Fig. 10 shows a course with different load changes and warning and tripping areas for error and fault messages.

As shown in FIG. 4, a consumer 1 is connected to a power supply network 3 via a counter 2. In the household, not every single consumer 1 is usually controlled via the meter in its power consumption, but the household itself represents a consumer 1. The functional analysis according to the invention can refer to the consumer located behind a meter, in the case of a household consequently to the totality of all consumer units. If the resolution refers to a single consumer unit, this would have to be provided with its own counter, which then this the

Subject of the functional analysis according to the invention

represents.

In industrial plants, for example, the

Cost control of individual machines or machine groups as consumers 1 counted over counter 2. At such machines 4 driven devices 5 are then connected via a corresponding output. Different loads on the driven devices 5 will act on the consumer 1 via the output 4. But also the

Consumer 1 may have its own burden. These loads cause an increased power consumption of the consumer 1 from the power grid 3.

Usually, the instantaneous power of the consumer 1 is measured via the counter 2 and a corresponding one

Pulse train to a consumption evaluation device 6

transmitted .

The pulse frequency can be influenced by changing the frequency power ratio. Typically, for example, a pulse weighting is defined in the counter such that a pulse represents the power of 0.1 to 1000 watts. That is, derived from the

Rotor disc rotation of conventional FERRARIS counters, a pulse is generated when, for example, 1000 watts are consumed. The higher the frequency of occurring impulses, the higher the recorded

Instantaneous power of the consumer. Now, if the pulses are assigned other power values, for example, only 200 watts, then it can be seen that this is the occurrence of pulses already done faster at the same instantaneous power. Accordingly, with the definition of this frequency power ratio, the sampling rate can be set. As shown in Figure 1, occur at the pulse output 7 of the counter 2, the pulses of the upper diagram. It can be seen that the pulse repetition frequencies changed significantly from section 8 to section 9, 10 and 11. So

represent the different repetition frequencies of the sections 8 to 11 a different height

Power consumption per unit time, i. a different instantaneous power consumed by the consumer 1 during the

Periods 8 to 11 is recorded, as shown in the diagram below in Figure 1. Such different load recordings during

different periods 8 to 11 then lead to a course, which is shown in Figure 2. Because the

Pulse repetition frequency f is proportional to the power p, Figure 2 shows either the image of the pulse repetition frequency over time or the power over time. As can be seen, in each case one period T in the diagram is one

Recognition of the Lastfolgemusters to recognize. FIG. 2 shows a normal operation, ie an operation in which the consumer 1 or the driven device 5 have a normal function.

As shown in Figure 3, is at an occurrence of a probable damage to the consumer 1 or the

driven device 5 a deviation of the

Lastfolgemusters of the normal pattern of Figure 2 clearly visible.

As shown in Figure 4, the pulse train from the pulse output 7 is now also given to a computer 12. This computer 12 now compares the pattern according to FIG the pattern of Figure 2, which he has stored as a normal pattern. By this comparison, he notes a conspicuousness and outputs an alarm signal. This can of course take the form of an acoustic or optical or other type of signal, for example an SMS notification. This is not shown in detail in Figure 4.

In Figure 2 and Figure 3 is also a lower one

Fault signal threshold 13 and an upper fault signaling threshold 14 located. These fault signal thresholds have the general function that falls below the lower

Fault threshold, as for example in a

Interruption of the pulse output 7 or at a

Shutdown of the consumer 1 can happen, each of which may constitute faults, usually triggered an alarm signal. In the same way is also a

Exceeding the upper fault threshold, for example in the event of an overload, signaled. As can be seen from FIG. 3, however, the disturbances are within the two fault thresholds and would normally not lead to the triggering of an interference signal. By the

However, the pattern matching method according to the invention will also be alarmed in the case of faults which are not covered by fault reporting thresholds 13 and 14. In a further embodiment, the

Performance curve of an asynchronous motor with connected delivery pump shown. Fig. 5 shows with the curve normal operation, in which only small fluctuations of

Power consumption occur. Differences in the individual load change periods are not recognizable.

A very similar course is shown in FIG. 6. In purely optical terms, the uniform curve of FIG. 5 appears to persist here. However, a slow-acting wear occurs, the mean of the power consumption quite easily and hardly increases noticeably. However, by the method according to the invention the slow increase 16 is visible, although no differences in the load change periods can be seen. The situation is different with FIG. 7. Here, the same measurement as in FIG. 5 was logged. However, there are significant differences compared to the normal pattern according to FIG. 5 here. Also here are the load change periods T _L clearly visible, each one revolution of the

Motor shaft or an output shaft of a connected gearbox correspond. In each case in a first sub-period 17 of a load change period T _L , a normal behavior is observed. However, in a second sub-period 18, a noticeable oscillation with a large amplitude of the recorded power P is recognizable before the curve returns to normal behavior in a third sub-period 19. This is due to a bearing failure, in each of which the second part of the period 18 of the rotation, the ease of the engine or the output shaft is difficult which leads to an increased power requirement.

In Fig. 8, the course 20 is at a secondary one

Overheating of a part, such as a warehouse, recognizable. In the first phase 21, the consumer still shows a normal behavior of the power consumption. In the second phase 22, a significant increase in the related power P can be seen. The warehouse heats up and gets increasingly heavier. Upon reaching a certain temperature of the bearing whose binding does not increase further and the power consumption remains at the high level in phase 23. The waveform 24 in Fig. 9 indicates unstable

Vibration behavior of the consumer (eg "rattling" of bearing parts or the like), which can lead to failure. Fig. 10 shows a course with different load changes and warning and tripping areas for error and fault messages. In the event of permanent load, overcurrent protection devices respond, such as thermal tripping motor protection switches. Below this threshold can be with the

inventive method, as already in Fig. 2

described, anticipating recognize and turn off critical states.

In summary, it can be stated that the

inventive method, comparable to a

medical electrocardiogram (ECG) is. The

Electrocardiogram (ECG) in medicine is the record of the sum of the electrical activities of all

Cardiac muscle fibers. Electrocardiogram is also called

Cardiac stress curve or also called heart letter.

By the method according to the invention it is possible to change in recorded amplitude sequences in the

To recognize and interpret load behavior, as shown in Figures 5 to 9. The solution according to the invention was preceded by the knowledge that changes in the amplitude curve in the case of an impulse specification of the current reference-dependent measurement from 1 Hz can provide information on the condition of the system, provided that historical data are available. Increasing the output frequency to 30 Hz up to 1 kHz, much more accurate statements can be made. In this respect, the amplitude sequence is always a reflection of the wear of the mechanics behind an electric motor drive or the energy efficiency or wear state of a thermoelectric system. The amplitude monitoring ("ECG") thus recognizes similar to the medical consideration of the heart rate and the heart rate

Heart rhythm of a biological organism, a possible negative change to the target state. The functional analysis according to the invention includes the fast (1 Hz to 30 kHz) recording of the sum of the mechanical loads and load changes, which is expressed in a temporary increase in the recorded electrical power.

Thus, the pulse train of the electrical load of an asynchronous motor is a reflection of the mechanics behind the drive. The rotor of the asynchronous motor turns always slower than the rotating field on the coils of the primary side. The speed at the operating point will always be a few percent below the associated synchronous speed

to adjust. This difference is called slip and is load-dependent. The load dependency forces a higher motor current. Talk about a permanent load

Overcurrent protection devices such as thermal triggers

Engine protection switch on. (see Fig. 12) Below this threshold, critical states can be anticipated and switched off with the ECG current.

From the measurements arise characteristic

Amplitude sequences that can be assigned to specific disturbance patterns. A calibration or adaptation to each connected electrical system is possible by the skilled person or by a self-adapting software. In the latter approach, a period of time is automatically declared the base amplitude sequence. The computer then monitors changes outside a certain tolerance range. Particular attention is paid to spontaneously changing or logarithmically changing amplitude sequences in a gate time t1 to tn. Thus, the inventive method can be used in the construction of an energy management system with low additional costs for the construction of such a system, a significant amount for quality assurance and avoidance of

Spontaneous failures on production systems afford. Characteristic amplitude sequences are:

- Normal operation (Fig. 5)

slowly drifting changes (FIG. 6)

- Changes in frictional resistance (Fig. 7) - Changes in temperature (Fig. 8)

- Changes in the vibration behavior (Fig. 9)

- Hide load changes, usual production-related fluctuation (Fig. 10)

From the amplitude sequences conclusions to a

Failure behavior can be drawn. Basically, the following approach has proven itself:

The recorded mean power values and real time values in the amplitude sequence of 1 Hz - 1 kHz allow functional conclusions. These are displayed in a suitable manner and generated as error messages.

It can be assumed that measuring points on technical systems for recording pressure, temperature,

Frictional losses, etc. in the sum can express themselves in specific amplitude sequences and can be selected. Consequently, the measured by Pulse counters

Power variation, expression of a specific error source.

The integration behavior of modern electrical

Pulse encoder counter allows sampling rates up to 30 kHz. The high-precision measurement of the measuring circuits guarantees a highly sensitive recording of the results of current, voltage and power consumption.

The announcing functional change in the direction of failure of an electrical system is always expressed in a drift, cyclic or periodic change in power consumption, z. B. in asynchronous motors.

Method for functional analysis of electrical consumers

LIST OF REFERENCE NUMBERS

1 consumer

2 counters

3 Stromversorgungsnet z

4 downforce

5 powered device

6 consumption evaluation device

7 pulse output

8 section

9 section

10 section

11 section

12 computers

13 upper fault signaling threshold

14 lower fault threshold

15 normal operation

16 rising curve

17 first part-period

18 second partial period

19 third part of the period

20 Course with secondary overheating

21 first phase second phase third phase

Claims

claims

1. A method for functional analysis of electrical loads, in which one of the consumer (1)

generated pattern of a characteristic parameter (F, P) and determined with a desired pattern of the

characteristic parameter (F, P) during a

Normal state of the consumer (1) (normal pattern) compared and a significant deviation

Alarm signal is generated, characterized gekennzei chnet that the electrical power consumption P of a consumer representing pulse train is generated such that the pulse frequency F represents the power P and the frequency-power ratio is adjusted so that the pulse frequency F is higher than a frequency of periodic load changes

(Lastwechselfrequenz) at the consumer (1) and that the pattern of the time course of the pulse frequency F or the power consumption P determined therefrom

Consumer is compared with the normal pattern and in case of deviation, the alarm signal is generated.

2. Method according to claim 1, characterized in that the pulse frequency F is at least the Ten times the load change frequency is.

3. The method according to claim 2, characterized in that the pulse frequency F is 10 to 100 times the load change frequency.

4. The method of claim 1 or 2, d a du r c h

The normal pattern from the pattern of the load changes of a previous one can not be used

Time interval is determined.

5. The method according to claim 4, characterized in that the pattern is determined from the average values of the power consumption P of a plurality of preceding pulse intervals T corresponding to one another.

6. The method according to claim 4 or 5, d a du r c h

This is the pattern of the

Load changes stored and from the normal pattern is determined.

7. The method according to claim 6, wherein a normal pattern is updated from respectively younger progressions of the pattern.

8. The method according to any one of the preceding claims, characterized gekennz egg chnet, the s the normal pattern is determined over at least two load changes.

9. Method according to one of the preceding claims, characterized in that the normal pattern is compressed in such a way that significant parts of the pattern are determined and only these are stored and the corresponding parts of the power consumption pattern are compared with the stored significant parts of the normal pattern.