Title of Invention

"AN IMPROVED POWER ANALYSER"

Abstract This invention relates to a power analyzer for monitoring and analyzing critical electrical parameters from a plurality of electrical instruments or electronic circuits simultaneously. The power analyzer has a plurality of voltage and current transducers adapted to be connected to a power source. The transducers are adapted to step down the input voltages and currents. A data acquisition card is connected to the output of said transducers. A host computer having a processing unit is connected to the output of said data acquisition card.
Full Text FIELD OF INVENTION
This invention relates to an improved power analyser for monitoring and analysis of different electrical parameters like voltage, current, frequency, harmonics, and transients which determine the quality of power in ac as well as dc electrical instruments or electronic circuits.
PRIOR ART
The monitoring and analysis of different electrical parameters is important to ensure the smooth functioning of different electrical/electronic instruments and protect them from intermittent power disturbances like sudden spikes, under and over voltages, frequency deviations and harmonic distortions. Sometimes these deviations may ultimately result in failure of the various equipments.
Traditional systems for monitoring power require installation of individual measuring devices to monitor specific electrical parameters like current, voltage or wattage. These devices could be analog or digital and these comprise of discrete current and voltage transducers.
However, these devices are not considered very efficient as the monitoring as well as analysis of various electrical parameters can not be done at a high speed with these devices. Further, separate measuring devices for each electrical parameters add to the overall maintenance cost of the system. These traditional systems for monitoring power are no longer in much use.
The improved type of power analysing systems presently available consist of dedicated hardware with embedded processors. Such type of systems calculate various electrical parameters such as rms & peak values of current & voltage, frequency, power, voltage sags & swells and frequency deviations with the help of embedded processors. These power analysers utilise sampling technique to analyse the input electrical parameters to calculate and display voltage transients, voltage sags, frequency deviations and harmonic distortion analysis in real time mode. The accuracy at which the different parameters can be calculated depends upon the sampling rate at
which the analog waveforms of the input signals are digitized. However, a limit is imposed upon the sampling rate because of the requirement of computing time needed by the embedded processor to calculate the various electrical parameters required to be displayed.
However, such type of power analysers, presently available, suffer from many disadvantages.
One major disadvantage of the presently available power analysers is that such systems utilise dedicated embedded processors with fixed performance parameters and thus lacking versatility in terms of upgradation of processor performance.
Another disadvantage of the known power analysers with dedicated embedded processor is that the speed of the analysis of the different electrical parameters is limited by the attributes of embedded processor which can not be changed.
Yet another disadvantage of the known power analysers is that the embedded processor of such systems can not be adopted to multifunctional role such as CRO or a normal PC.
Still further disadvantage of the known power analysers is that such analysers employ lower sampling rate to sample the input signals thus limiting the accuracy of measurement of different power parameters.
Yet another disadvantage of the known power analysers is that these analysers can not monitor the transients and interruptions of very short duration because of lower sampling rates employed.
Still further disadvantage of known power analysers is that these analysers employ LED or LCD display device having lower resolutions.
Yet another disadvantage of the known power analysers is that these analysers suffer from limited memory of the embedded processors and thus putting a limitation on the amount of data which can be stored and analysed. The memory capacity available in the known power analysers is of the order of 2MB only.
Still further disadvantage of the known power analysers is that simultaneous display of both current and voltage in real time is not possible in such systems.
Yet another drawback of these power analysers known in the art is that the number of input channels available for analysis of input signals is limited to a maximum value of 6 only.
Still further disadvantage of the known power analysers is that recording and playback of voltage _and current waveforms is not possible in these power analysers.
OBJECTS OF THE PRESENT INVENTION
Primary object of the invention is to propose an improved power analyser fully integrated with a personal computer and a high resolution monitor to obviate the above mentioned disadvantages.
Yet another object of the invention is to propose an improved power analyser which can monitor, analyse and display all the critical electrical parameters of ac as well as dc electrical instruments or electronic circuits at a very high speed.
Still another object of the invention is to propose an improved power analyser which has higher measurement accuracy of 25 micro volt, 25 micro ampere and 0.1 Hz for measurement of voltage, current and frequency respectively.
Yet another object of the invention is to propose an improved power analyser which can monitor, analyse and display all the critical electrical parameters in real time mode.
Still another object of the invention is to propose an improved power analyser which can monitor and analyse all the critical electrical parameters from a plurality of electrical instruments/electronic circuits simultaneously.
Yet another object of the invention is to propose an improved power analyser which has capability to monitor power parameters from a total number of 16 input channels.
Still further object of the invention is to propose an improved power analyser which can sample the input analog signals at a higher frequency of 156 KHz thus ensuring higher accuracy of all the measured electrical parameters.
Yet another object of the invention is to propose an improved power analyser which has ability to store the input data as well as calculated electrical parameters in the memory location of host personal computer .
Still further object of the invention is to propose an improved power analyser in which the host computer can be utilised to work as a CRO as well as like any other.personal computer thereby enhancing the utility of the host computer.
Yet another object of the invention is to propose an improved power analyser which can detect any voltage transient and interruption having time duration as low as 50ยต, seconds.
Still further object of the invention is to propose an improved power analyser which can perform harmonic distortion analysis up to 9th harmonic of fundamental.
Still further object of the invention is to propose an improved power analyser which can operate in six different modes i.e., Continuous monitoring, Real time waveform display, Out of limit checking, Harmonic analysis, Impulse monitoring and Graphics playback modes depending upon the specific requirement.
Yet another object of the invention is to propose an improved power analyser having a custom built comprehensive computer program resident in the processor of the host computer working as a user interface allowing the user to process input data in a predetermined manner.
Still further object of the invention is to propose an improved power analyser in which the host computer utilizes a monitor with a higher resolution of 1280 x 1024 pixies.
Still another object of the invention is to propose an improved power analyser in which the host computer can be upgraded in terms of processing speed as well as memory capacity thus offering flexibility.
Yet another object of the invention is to propose an improved power analyser which is flexible, easy to maintain and ruggedised.
SUMMERY OF THE INVENTION
According to this invention there is provided an improved power analyzer for monitoring and analyzing critical electrical parameters from a plurality of electrical instruments or electronic circuits simultaneously having voltage transducer (1), current transducer (2) data acquisition card (3) host computer (4) power lines (5,6) multiplexes (7) instrument amplifier (8) gain amplifier (9) characterised by:
i) a plurality of voltage (1) and current (2) transducers adapted to be
connected to a power source, ii) said transducers adapted to step down the input voltages and
currents, iii) a data acquisition card (3) connected to the output of said
transducers,
iv) a host computer (4) having a processing unit connected to the output of said data acquisition card (3).
v) The present invention provides an improved power analyser fully integrated with a host Personal Computer and a high resolution monitor which can continuously sample the plurality of electrical parameters at very high frequency and display all the critical parameters, waveforms and result of harmonic distortion analysis in real time in six different modes depending upon the specific need of the operation. This power analyser has multipurpose role and can be utilised for continues monitoring of the performance of UPS systems, CVTs and output of variety of electronics circuits. The proposed system can monitor up to 16 input current and voltage signals and thus has the capacity to monitor the performance of a number of electrical equipments. The power analyser can continuously monitor and display critical parameters like current, voltage, voltage transients, voltage sags, voltage swells, current variation, frequency variation, rms and perk values of voltage and current, crest factor and total harmonic distorting of any ac well as dc electrical equipment. The system can operate in Continuous monitoring, Real time waveform display, Out of limit checking, Harmonic analysis, Impulse monitoring and Graphics playback modes depending upon the specific requirement. The system has capacity to monitor as well as analysis various electrical input parameters at a high speed with great accuracy.
The system comprises of voltage and current transducers which are directly hooked on to the power line. These transducers step down the input voltages and currents which are subsequently fed to the data acquisition card
which acts as a interface between input signals and the host computer. The data acquisition card comprises of multiplexer, instrument amplifier, gain amplifier, sample and hold circuit and a 12 bit A/D converter. The data acquisition card samples these input signals at a fixed sampling interval, converts the data to digital form and send it to host computer for further processing. The custom built computer program written in C language and resident in the host computer acts as a interface between user and the complete system. The host computer process this data in predetermined manner and displays the various critical electrical parameters in high resolution computer monitor in real time manner.
DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE DRAWING
Additional advantages and features of the present invention will become apparent from the detailed description of the preferred embodiment which has been described and illustrated with the help of following drawing wherein
Fig (1) describes the block diagram of the power analyser.
Referring to Fig. 1 the present power analyser comprises of voltage transducer (1), current transducer (2), data acquisition card (3) and host computer (4). The probes of the voltage transducer (1) and current transducer (2) are connected to the power line (5,6). There are total 16 such voltage and current transducers with clamps which can be utilised to monitor plurality of input signals simultaneously. The voltage transducer (1) steps down the input voltage to a value in a range from -10 to +10 volt which can be processed by the data acquisition card (3). Similarly current transducer (2) converts the input current signal to equivalent voltage within a range from -10 to + 10 volt which is within acceptable range of data acquisition card. Data acquisition card acts as an interface between input signals and host computer having 16 input channels corresponding to 16 voltage and current transducers. In the data acquisition card, these input signals coming from the 16 input channels are synchronised and selected in a predetermined manner by the multiplexer (7). The signal coming from the multiplexer (7) is amplified by instrument amplifier (8) having a fixed value of magnification and further amplified by the gain amplifier (9) having
selectable amplifications of 1, 10, 100 and 1000. This amplified signal is sampled at higher frequency by sample and hold circuit (10) in a predetermined manner. The sampling frequency in decided by the Nyquist criteria. According to this criteria the sampling frequency should be greater or equal to the twice the value of signal frequency. The output of the sample and hold circuit (10) is converted to digital form by 12 bit A/D converter (11). The digitised data is processed by the main processing unit (12) of the host computer (4). Main processing unit (12) of the host computer synchronises the input digitised data from the data acquisition card (3) to high resolution monitor (14). Disk storage (13) of the host computer (4) can be utilised to store the output digitised data from the data acquisition card for further processing, analysing and displaying on the high resolution monitor (14).
The custom built program written in C language resident in the host personal computer acts as a user interface allowing user to specify various operating modes, sampling parameters, threshold limits, storage options and to perform a variety of tasks such as logging of text data, limit checking, graphics display, playing back current and voltage waveform, computing harmonic distortion up to 9th harmonic etc.
The system can operate in six different modes which can be selected depending upon the specific requirements. These operating modes along with their specific functions have been described briefly in the following.
1. CONTINUOUS MONITORING MODE
This mode displays and records rms and peak values of voltage, current, and frequency with time stamp in text mode and sounds buzzer in case of power supply failure.
2. REAL TIME WAVEFORM DISPLAY MODE
This mode displays and records the voltage and current waveforms with site location, time stamp, frequency, rms value, peak value and crest factor.
3. OUT OF LIMIT CHECKING MODE
This mode records the voltage and current disturbances with time of occurrence, magnitude and duration in milliseconds and sounds an alarm whenever the rms values exceed beyond the predefined limits set by the user.
4. HARMONIC ANALYSIS MODE
This mode computes and records Total Harmonic Distortion for voltage based on 2048 point FFT up to 9th harmonic in real time with time stamp.
5. IMPULSE MONITORING MODE
This mode monitors for any transient in voltage waveform for a duration more than 50 micro seconds
6. GRAPHICS PLAYBACK MODE
This mode plays back and prints the voltage and current waveforms, transients and spectral content recorded in the other modes.
The embodiment of the invention which has been set forth above was for the purpose of illustration and it is not intended to limit the scope of invention. It is to be understood that various changes and modifications may be made in the invention described above by those skilled in the art without departing from the scope of the invention which has been defined by following claims.



WE CLAIM:
1. An improved power analyzer for monitoring and analyzing critical
electrical parameters from a plurality of electrical instruments or
electronic circuits simultaneously having voltage transducer (1),
current transducer (2) data acquisition card (3) host computer (4)
power lines (5,6) multiplexes (7) instrument amplifier (8) gain
amplifier (9) characterised by:-
i) a plurality of voltage (1) and current (2) transducers adapted to
be connected to a power source, ii) said transducers adapted to step down the input voltages and
currents, iii) a data acquisition card (3) connected to the output of said
transducers, iv) a host computer (4) having a processing unit connected to the
output of said data acquisition card (3).
2. An improved power analyzer as claimed in claim 1 wherein said data
acquisition card (3) comprises a multiplexer (7) connected to an
amplifier, a sampler connected to the output of said amplifier.
3. An improved power analyzer as claimed in claim 2 wherein said
sampler is connected to sampler circuit which in turn is connected to
a converter.
4. An improved power analyzer as claimed in claim 2 wherein said
amplifier comprises an instrument amplifier (8) and a gain amplifier
(9).
5. An improved power analyzer as claimed in claim 3 wherein said
sample circuit comprises a sample and hold circuit (10).
6. An improved power analyzer substantially as herein described and
illustrated with reference to accompanying drawings.



Documents:

546-del-1999-abstract.pdf

546-del-1999-claims.pdf

546-del-1999-correspondence-others.pdf

546-del-1999-correspondence-po.pdf

546-del-1999-description (complete).pdf

546-del-1999-drawings.pdf

546-del-1999-form-1.pdf

546-del-1999-form-19.pdf

546-del-1999-form-2.pdf

546-del-1999-form-3.pdf

546-del-1999-gpa.pdf


Patent Number 233605
Indian Patent Application Number 546/DEL/1999
PG Journal Number 14/2009
Publication Date 27-Mar-2009
Grant Date 31-Mar-2009
Date of Filing 08-Apr-1999
Name of Patentee THE CHIEF CONTROLLER RESEARCH & DEVELOPMENT, MINISTRY OF DEFENCE, GOVERNMENT OF INDIA
Applicant Address B-341, SENA BHAWAN, DHO P.O., NEW DELHI-110011
Inventors:
# Inventor's Name Inventor's Address
1 PRAKASH CHANDRA GOPE INTERIM TEST RANGE, CHANDIPUR
2 UDAYAVARMA JAYAKRISHNAN INTERIM TEST RANGE, CHANDIPUR
3 NEELAMADHAB BISWAL INTERIM TEST RANGE, CHANDIPUR
PCT International Classification Number G01R 31/40
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA