MXPA01001895A - System and method for frequency compensation in an energy meter - Google Patents

Abstract

A system and method for improving the ability of an electronic meter (14) to make measurements on signals to determine content of different frequencies, and harmonics of the fundamental frequency, of AC signals (voltages and currents). The line frequency is determined and compensated for prior to performing frequency-dependent parameter measurements or determining frequency-dependent parameters.

Description

SYSTEM AND METHOD FOR FREQUENCY COMPENSATION IN AN ENERGY METER FIELD OF THE INVENTION The present invention relates generally to the field of electronic energy meters. More particularly, the present invention relates to electronic energy meters with systems for compensating for frequency variations in the electrical power supply that is provided to the energy meter.

BACKGROUND OF THE INVENTION The transfer of energy in volume through alternating voltages and currents is inherently made at some nominal frequency, typically 50 or 60 Hz. Historically, small variations in the nominal line frequency were of little concern for measurement of electromechanics watts / hour. Electromechanical meters are limited to basic metrics, such as, watts / hours or VAR / hours using loose phase change transformers, and the accuracy of the results was not generally frequency dependent. The recent deregulation of the public services industry has created a market for products that facilitate the efficient distribution and monitoring of energy electric In the past, public services have constituted an infrastructure that did not provide adequate information to monitor and adjust the electric power in the distribution system. One reason for monitoring line frequency is the greater interest and concern for the accurate measurement of the harmonics of the energy system for public services. Historically, measurement practices had only a minor concern with harmonics, but the current interest is much higher due to an increase in customer loads that generate harmonics in a public service system. These harmonics can cause VA loads on transformers that are higher than expected, as well as cause a customer's account to actually go down when the harmonic energy is indeed being extracted from the utility system. Frequency compensation is desired to obtain accurate measurements of the harmonic quantities in the voltage or current signals. In the past few years, electronic energy meters have moved more into the digital world, with analog-to-digital converters (ADCs) and digital processing. More recently, digital electricity meters have begun including additional instrumentation features that allow the user to read the value readings almost instantaneously, such as phase angles from one voltage to another voltage, phase angles from one current to one voltage, energy factors per phase, voltages per phase, currents per phase, harmonics of voltage per phase, harmonics per phase, and watts per phase and system, reactive volts-amperes (VARs) per phase and system, and total harmonic distortions for voltages and currents per phase. One problem that must be considered is the problem of dependence on frequency, especially on values such as voltage harmonics per phase. Digital meters tend to repetitively process samples at fixed time intervals and, although some quantities can be calculated, for a set of samples at a time, other quantities are desirably averaged over one or more cyclic line periods. Because a fixed sampling rate implies a fixed number of samples per cyclic line period, the results are generally compensated by variations in the line frequency to avoid having errant results. A typical means for adjusting RMS voltages, RMS currents and apparent volt-amperes (VA) energy is to detect the zero crossings of a signal and average the results by the number of samples incurred during that flexible period. However, other more complicated calculations, such as harmonics, can not be fully compensated after measurements and interim calculations are made.

COMPENDIUM OF THE INVENTION The present invention is directed to a system and method for improving the capacity of an electronic meter to make measurements on signals in order to determine the content of different frequencies, and the harmonics of the fundamental frequency, of AC signals, and also of the energy (watt, VAR, and VA) from the product of the voltage and the specific frequency currents. The line frequency is determined and compensated before making the measurements of the frequency-dependent parameters or determining the frequency-dependent parameters. In one embodiment within the scope of the present invention, there is provided a method of compensating a frequency variation in electrical energy provided to an energy meter by means of a type of service, which comprises the steps of: measuring a frequency of electric power; select a reference waveform that has a positive zero crossing; synchronize two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; obtain an input signal waveform; determining a magnitude of a signal of the ideal frequency within the waveform of the input signal; and determining an angle of the ideal frequency signal within the waveform of the input signal. The resulting amounts can be used to quantify normally the unwanted harmonics on the individual signals, as well as to determine the angles between the fundamentals of the signals distorted in another way. The foregoing and other aspects of the present invention will become clearer from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram showing the functional components of an example meter and their interfaces according to the present invention. Figures 2A and 2B show an exemplary DFT method, according to the present invention.

DESCRIPTION OF THE EXAMPLE MODALITIES AND BEST MODE The present invention is directed to a system and method for improving the capacity of an electronic meter to make measurements on signals to determine the content of different frequencies, and the harmonics of the fundamental frequency of the signals. AC signals (voltage and current). The line frequency is determined and compensated before making the measurements of the frequency-dependent parameters, or of determining the frequency-dependent parameters.

Most current solid-state energy meters digitally sample current signals in one to three different phases, and process them to normally generate quantities for billing purposes (such as watts / hours, VAR / hours or VA / hours) . They are also becoming able to determine a wide variety of instrumentation quantities. As an improvement, these meters are also capable of processing these quantities to determine both the validity of the wired installation external to the electronic meter itself, as well as other unusual parameters, such as harmonics. In accordance with the present invention, systems and methods for detection and compensation of line frequency variation will now be described with reference to the figures. It will be appreciated by those of ordinary skill in the art that the description given herein with respect to the figures is for purposes of exemplification only and is not intended to limit the scope of the invention in any way. For example, during the description of the preferred embodiment of the method and detection system, an example meter is used to illustrate the invention; however, these examples are merely for the purpose of clearly describing the methods and systems of the present invention and are not intended to limit the invention. Moreover, example applications are used throughout the description, where the present invention in conjunction with a particular electronic energy meter. This meter does not attempt to limit the invention, because the invention is equally applicable to other meter systems. The present invention provides detection and compensation characteristics of line frequency variation in relation to the measurement of electrical energy of a single phase or multiple phases. Figure 1 is a block diagram showing the functional components of an example meter, and their interfaces to which the present invention is applied. The meter is described in the pending TCP request entitled "ENERGY METER ITH POWER QUALITY MONITORING AND DIAGNOSTIC SYSTEM", Number TCP / US97 / 18547 which has the international filing date of October 16, 1997 (Case Number ABME-0237) which is incorporated herein by reference. As shown in Figure 1, a meter for measuring the three-phase electric power preferably includes a visual display of digital LCD 30, an integrated circuit (IC) 14 to the meter that preferably comprises A / D converters and a programmable DSP and a microcontroller 16. The analog voltage and current signals propagating over the power distribution lines between the power generator of the electric service provider and the users of the electric power are detected by the voltage dividers 12A, 12B, 12C, and current transformers or shunts 18A, 18B, 18C, respectively. The outputs of the resistive dividers 12A-12C and the current transformers 18A-18C, or the detected voltage and current signals are provided as inputs to the IC 14 of the meter. The A / D converters in the IC 14 of the meter convert the detected voltage and current signals into digital representations of the analog voltage and current signals. In a preferred embodiment, the A / D conversion is carried out as described in U.S. Patent Number 5,544,089, dated August 6, 1996, and entitled "PROGRAMMABLE ELECTRICAL METER USING MULTIPLEXED ANALOG-TO-DIGITAL CONVERTERS "assigned to ABB Power T & D Company. Then, the digital representations of voltage and current are introduced to the crocuster 16 through an IIC bus 36. The microcontroller 16 is preferably interconnected with the IC 14 of the meter and with one or more memory devices through an IIC bus. 36. A memory, preferably a non-volatile memory, such as an EEPROM 35, is provided for storing the nominal phase voltage and current data and the threshold data, as well as the programs and program data. After energization after installation, a lack of power, or a communication that alters the data, for example, the selected data stored in the EEPROM 35, can be downloaded to the RAM of the program and to the associated data RAM inside the IC 14 of the meter, as shown in Figure 1. The DSP under the control of the microcontroller 16, processes the digital voltage signals and current according to the programs downloaded and the data stored in the RAM of the program and in the respective data RAM. To perform the measurements and the line frequency compensation, the IC 14 of the meter monitors the line frequency, for example, during two line cycles. It should be understood that the number of line cycles is preferably programmable and a different number of line cycles may be used for designated measurements. Following the energization in the installation, a service test can be performed, identify and / or verify the electric service. The meter can be pre-programmed for use with a designated service, c can determine the service using a service test. When the service test is used to identify the electric service, an initial determination of the number of active elements is made. For this purpose, the voltage of each element is checked (that is, 1, 2, or 3 elements). Once the number of items is identified, many types of service can be removed from the list of possible service types. Then you can calculate the angle of phase voltage in relation to phase A, and is compared with each phase angle to determine abe or cba rotations with respect to the remaining possible services. If a valid service is found from the phase angle comparisons, the preferred service voltage is determined by comparing the RMS voltage measurements for each phase with nominal phase voltages for the identified service. If the rated service voltage for the identified service matches the measured values within an acceptable tolerance range, a valid service is identified and preferably phase rotation, service voltage, and type of service are displayed. The service can be secured, that is, the service information is stored in a memory, preferably a non-volatile memory, such as the EEPROM 35, manually or automatically. The types of service include Y of 4 wires, Y of 3 wires, delta of 4 wires, delta of 3 wires, or a single phase. When the type of service is known in advance and secured, the service test preferably checks to ensure that each element is receiving the phase potential and that the phase angles are within a previously determined percentage of the nominal phase angles. for the known service. The voltages per phase are also measured and compared with the nominal service voltages to determine if they are within a tolerance range previously defined of the nominal phase voltages. If the voltages and phase angles are within the specified ranges, the phase rotation, the service voltage, and the type of service in the visual display of the meter are displayed. If a valid service is not found, or the service test fails, a system error code indicating an invalid service is displayed, and secured in the visual display to ensure that the failure is recorded and evaluated to correct the error. The meter of Figure 1 also provides remote reading of the meter, remote monitoring of the power quality, and reprogramming through an optical port 40 and / or an optional connector 38. Although optical communications can be used in connection with the optical port 40, the optional connector 38 can be adapted for RF communications or electronic communications by modem, for example. The systems for performing line frequency detection and compensation according to the present invention are preferably implemented in firmware, where these operations are enabled by correct programming of the data tables. However, the system of the present invention can be implemented in computers for general purposes, using the software, or exclusively in a hardware for special purposes, or in a combination of the two.

The type of service with which the meter is connected is determined as described above. After the type of service is determined, the voltage magnitudes are verified per phase. If the voltage magnitudes per phase fall within the permissible parameters for all phases, then a nominal service voltage is determined. The determination of a valid type and a valid nominal service voltage for this type define the detection of a valid service. Phase angles from voltage to voltage are used in determining the type of service. The determination of the phase angle can be done in a different number of ways, including counting samples between zero-crossing of similar voltage or by making a Discrete Fourier Transformation (DFT) between one of the phase voltages of interest and an ideal signal triggered by the other voltage of interest. Most techniques for measuring phase angles between two sine signals are frequency dependent. Therefore, the determination of the type of service with which the meter is connected is an example of a frequency-dependent determination. Assuming that the energy meter does its discrete sampling at fixed time intervals, the equivalent angle between each sample is directly proportional to the line frequency. This proportionality with the line frequency causes errors in the measurement of the phase angle from voltage to voltage in both methods described above, unless frequency compensation is used. To perform the frequency compensation, the present frequency is desirably known. When it is known that the meter is sampling the signals at known discrete time intervals, the count of the number of samples between similar zeroes (line cycles) can be used as a method to determine the present line frequency. More than one line cycle can be used if the average number of samples per line cycle is calculated. Any whole number of line cycles (greater than or equal to one) can be used, but the greater the number of line cycles, the more accurate the value of the line frequency present will be.

USE OF THE DISCRETE FOURIER TRANSFORMER An exemplary method of compensation for line frequency variations according to the present invention is shown in Figures 2A and 2B. A Discrete Fourier Transformer is used to determine the content of a particular frequency signal within an input signal. A particular frequency will be referred to herein as an ideal frequency. A reference waveform is also used to synchronize the Ideal Wave Forms described later. The input signal is referred to herein as the Input Waveform, and can be made of a fundamental frequency, and any number of its harmonics. As described in more detail below, the Discrete Fourier Transformer is determined by multiplying the Input Waveform by two Ideal Wave Forms of the same ideal frequency. An Ideal Waveform is 90 degrees out of phase, with the other Ideal Waveform; that is, an Ideal Waveform is the component in phase and the other Ideal Waveform is the quadrature component. The Input Waveform is therefore multiplied separately by the two Ideal Wave Forms. In the preferred digital sampling implementation, the products are averaged separately over a programmable number, X, of complete line cycles. A single line cycle is used for the description of the present for simplicity of explanation, but the same concepts apply for use with the average over multiple line cycles. You want to determine exactly the phase angle between the fundamental frequencies of two signals in real time (the Input Waveform and the reference waveform). To determine exactly the phase angle using a Discrete Fourier Transformer, the actual line frequency is used as the ideal frequency of the two Ideal waveforms, and the two ideal waveforms are synchronized with the reference waveform. It should be noted that the reference waveform is not being analyzed, but is merely being used as a reference. If the actual line frequency (of the Input Waveform and the reference waveform) is not known and differs from the nominal, and the two Ideal Waveforms are on the nominal line frequency, then the result will be An error when comparing with the real angle. Additionally, the frequency synchronization problems also lead to errors in the calculated magnitudes, when compared with the actual magnitudes. Furthermore, in a digital sampling system, the reference or synchronization of an Ideal Waveform with a repetitive waveform in real time (such as the reference waveform) presents some problems. Any error in synchronization results in a direct error in the resulting phase angle value. A reference point in a repetitive reference waveform is zero crossing. Crossings to zero are determined by calculating the product of two successive samples. If the product is positive, then zero crossing has not occurred. If the product is negative and the first sample was positive, a negative zero crossing has occurred. If the product is negative and the first sample was negative, a positive zero crossing has occurred. The variation in the phase angles of the harmonics can cause that the crosses to zero do not happen exactly in the point of zero degree of the fundamental frequency. In real-world applications, voltages are normally determined by the fundamental and a small variation in the angular location of the zero crossing does not make a significant difference. The objective is to synchronize the Ideal Waveform with the reference waveform. However, if the Ideal Waveform does not start until a zero crossing is seen in the actual sampling data, the Ideal Waveform could be delayed from the actual waveform by as much as the time of a sample. To solve the previously observed problems, different methods can be used. The knowledge of the present line frequency can be used to compensate for the problem of the variation of the line frequency of the nominal. The knowledge of the present line frequency can be carried out (1) by measuring the line frequency present just before the measurement of any frequency-dependent amount, or (2) by periodically measuring the frequency of the line frequency. present line and storage of its averaged value. The first method takes more time when the measurement is desired, but results in a detected line frequency closer to the time of measurement.

Actual measurement, and also uses less memory storage, when purchased with the second method to determine an average line frequency on a continuous basis. However, the method of averaging allows to have a greater precision than the longer fact of averaging the line frequency, and an improvement in the speed because only the measurement needs to be done (without the additional time required to make a first measurement). of frequency) . The power line frequency does not normally change for large amounts, and usually not very fast. Thus, the preferred implementation uses a slight variation of the first method mentioned above. In this method, there may be a number of measurements made that all depend on the frequency. These measurements are grouped together, so that they can be made as soon as possible one after the other, and a single measurement of the line frequency is made at the beginning of the measurement sequence, and the same frequency set as the ideal frequency to generate the two Ideal Wave Forms for each Measurement of Discrete Fourier Transformer. Prior to step 101, an instrumentation request is made from microcontroller 16 to IC 14 of the meter to determine the actual line frequency. Then in step 101, IC 14 of the meter receives a request from compensated line frequency, from the microcontroller 16, together with the number of line cycles, X, to be used in the sample. In step 105, a reference signal (ie, a reference waveform) is sampled. In step 109, the reference waveform is verified to determine if it has zero crossing. If it does not, another sample of the reference waveform is obtained in step 105. If a positive zero crossing of the reference form is detected in step 109, then the ideal waveforms are synchronized and initialized. step 113. A counter is cycled down, in the number of line cycles to be sampled, in step 117. The accumulators of sum 1 and 2 are initialized (referring to a sum-in-phase accumulator already a quadrature sum accumulator, respectively) and the sample count (set to zero) in step 121. A sample of the Input Waveform is obtained in step 125. The Input Waveform is multiplied by the Ideal waveform in phase, in step 129, and the product is added to the sum-in-phase accumulator. The Input Waveform is multiplied by the quadrature of the Ideal Waveform, in step 133, and the product is added to the sum quadrature accumulator. In step 137, the sample count is incremented, and step 141 samples the reference waveform to determine if a positive zero crossing has occurred. If the The reference waveform is not positive to zero, another sample of the Input Waveform is obtained, and the process continues in step 125. If the reference waveform is at a positive zero crossing in the step 141, then the cycle counter is decreased downward, in step 145. In step 149, the cycle counter value is checked downward. If the value is not zero, then another sample of the Input Waveform is obtained, and the process continues in step 125. If the value of the downstream cycle counter is set to zero in step 149, then the quantity in phase and the quantity in quadrature in step 153. The quantity in phase is equal to the value in the accumulator of sum in phase divided by the count of samples, and the quantity in quadrature is equal to the accumulator of sum in quadrature divided by the sample count. The resulting phase and quadrature quantities (averages) are proportional to the in-phase and quadrature components of the ideal frequency signal within the Input Waveform. The magnitude of the resulting phase and quadrature quantities (averages) are determined in step 161, by the square root of the sum of the squares of the quantities in phase and in quadrature. The magnitude is equivalent to the product of the RMS value of the ideal frequency signal within the Input Waveform and the RMS value of any of the Ideal Waveforms. (It is assumed that RMS values of both Ideal Waveforms are the same. Normally, the peak value of the Ideal Wave Forms is 1, resulting in an RMS value of (1/2).) So dividing the resulting quantity by the RMS value of one of the Ideal Wave Forms is determines the magnitude of the ideal frequency signal within the Input Waveform. The angle of the ideal frequency signal is determined within the Input Waveform is determined, in step 165, with respect to the ideal input signals by using the terms in phase and in quadrature. The resulting phase angle is determined by: Sign of quantity sign Calculation of angle quantity in quadrature phase (in degrees) + + Arctan (quadrature / in phase) + 0 ° + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 360 ° Although the terms in phase and quadrature are a function of the RMS values of the two Ideal Wave Forms, the RMS values of the two Ideal Wave Forms do not have to be removed as in the magnitude determination. Because they have identical values in both terms in phase and in quadrature, and the function arctan is executed over the quotient of the quadrature and in phase values, the RMS values are canceled from the two Ideal Wave Forms. For the determination of the voltage-to-voltage phase angle of the fundamental line frequency, the sample count is less complex, but the use of the Discrete Fourier Transformer for this application allows a common function to be used for multiple purposes. In addition, for the detection of nominal phase angles, this functionality allows detecting the values of the individual harmonics of higher frequencies. The availability of this functionality, in addition to the ability to calculate the RMS quantities, makes it possible to calculate the total harmonic distortion quantities. Accordingly, the present invention adjusts variable frequency measurements, due to variations in line frequency, by determining the line frequency before the measurement of the variable amount of frequency. In addition, the adjustment is made by changing the ideal frequency of the two Ideal Wave Forms used for the phase and quadrature measurements. Moreover, the present line frequency is determined either by measuring the frequency immediately before a measurement, or on a continuous repeating basis, and by using the last detected value as the present line frequency.

Although illustrated and described herein with reference to certain specific embodiments, the present invention, however, is not intended to be limited to the details shown. Rather, various modifications can be made to the details within the scope and range of equivalents of the claims and without departing from the invention.

Claims (43)

1. CLAIMS 1. A method for measuring the frequency-dependent electrical parameters by means of an energy meter in an electrical system that provides electric power having a variable frequency, which comprises the steps of: measuring a frequency of electrical energy; select a reference waveform that has a positive zero crossing; synchronize two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; get a waveform of the input signal; and determining a magnitude of a signal of the ideal frequency within the waveform of the input signal, wherein the two ideal waveforms are a function of the frequency, and are approximately 90 degrees out of phase one with the another, an ideal waveform representing one component in phase, and the other ideal waveform representing a quadrature component.
2. 2. The method according to claim 1, wherein the step of measuring the frequency comprises the steps of determining a time interval between a plurality of samples of a signal waveform, and counting a number of samples between a plurality of zero crossings of this signal waveform. The method according to claim 1, which further comprises the step of determining an angle of the signal of the ideal frequency within the waveform of the input signal with respect to the reference waveform. The method according to claim 1, which further comprises the steps of: multiplying the waveform of the input signal by the ideal waveform in phase to produce a product in phase for each sample of a plurality of samples in a line cycle, for at least one line cycle; add the product in phase for each sample to an in-phase adder accumulator to produce a sum-in-phase value; multiplying the waveform of the input signal by the ideal quadrature waveform to produce a quadrature product for each sample of the plurality of samples in a line cycle, for the plurality of line cycles; and add the product in quadrature for each sample to a quadrature summing accumulator, to produce a quadrature sum value. 5. The method according to claim 4, which further comprises the step of determining a quantity in phase and a quantity in quadrature. The method according to claim 5, which further comprises the step of counting a number of samples in the plurality of line cycles to determine a sample count, wherein the amount in phase = the sum value in phase / the sample count; and the quantity in quadrature = the value of sum in quadrature / the sample count. The method according to claim 5, wherein the magnitude and the angle of the signal of the ideal frequency within the waveform of the input signal, respond to the quantity in phase and to the quantity in quadrature. The method according to claim 7, which further comprises the step of determining a magnitude of the ideal frequency signal by a square root of the sum of the squares of the quantities in phase and in quadrature, multiplied by a Scale factor that is a function of the RMS value of one of the ideal waveforms. The method according to claim 7, wherein the step of determining the angle comprises determining this angle according to the table: Sign of the CanSign of the Calculation of angle in phase tity in cua (in degrees) dratura + + Arctan (quadrature / in phase) + 0o + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° + - Arctan (quadrature / in phase) + 360 ° 10. A system for measuring the frequency-dependent electrical parameters by means of an energy meter in an electrical system that provides electrical power that has a variable frequency by means of a type of service , which includes: an element to measure a frequency of electrical energy; an element for selecting a reference waveform having a positive zero crossing; an element for synchronizing two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; an element for obtaining a waveform of the input signal; and an element for determining a magnitude of a signal of the ideal frequency within the waveform of the input signal, wherein the two ideal waveforms are a function of the frequency, and are at approximately 90 degrees out of phase with each other, an ideal waveform representing one component in phase, and the other ideal waveform representing a quadrature component. The system according to claim 10, wherein the element for measuring the frequency comprises an element for determining a time interval between a plurality of samples of a signal waveform, and an element for counting a number of samples between a plurality of zero crossings of the waveform of the signal. The system according to claim 10, which further comprises an element for determining an angle of the signal of the ideal frequency within the waveform of the input signal with respect to the reference waveform. The system according to claim 10, which further comprises: an element for multiplying the waveform of the input signal by the ideal waveform in phase, to produce a product in phase for each sample of a plurality of samples in a line cycle for at least one line cycle; an element to add the product in phase for each sample to an in-phase adder accumulator, to produce a sum value in phase; an element to multiply the waveform of the input signal by the ideal quadrature waveform, to produce a quadrature product for each sample of the plurality of samples in a line cycle, for the plurality of line cycles; and an element to add the product in quadrature for each sample to a quadrature summing accumulator, to produce a quadrature sum value. The system according to claim 13, which further comprises an element for determining a quantity in phase and a quantity in quadrature. The system according to claim 14, which further comprises an element for counting a number of samples in the plurality of line cycles, to determine a sample count, wherein the quantity in phase = the sum value in phase / the sample count; and the quantity in quadrature = the value of sum in quadrature / the sample count. 16. The system according to claim 14, wherein the magnitude of the signal angle of the ideal frequency within the waveform of the input signal, respond to the quantity in phase and the quantity in quadrature. 17. The system according to claim 16, which further comprises an element for determining a magnitude of the ideal frequency by means of a square root of the sum of the squares of the quantities in phase and in quadrature, multiplied by a scale factor that is a function of the RMS value of one of the ideal waveforms. The system according to claim 16, wherein the element for determining the angle comprises an element for determining this angle according to the table. Sign of the can- Sign of the can- Calculation of angle in phase tidad in cua- (in degrees) dratura + + Arctan (quadrature / in phase) + 0o + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° + - Arctan (quadrature / in phase) + 360 ° 19. An apparatus comprising a storage element that stores software that measures the frequency-dependent electrical parameters in an electrical system that provides electrical energy having a variable frequency, by means of an energy meter, and performs the steps of: measuring a frequency of the electric energy; select a reference waveform that has a positive zero crossing; synchronize two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; get a waveform of the signal from entry; and determining a magnitude of a signal of the ideal frequency within the waveform of the input signal, wherein the two ideal waveforms are a function of the frequency, and are approximately 90 degrees out of phase one with the other, an ideal waveform representing a component in phase, and the other ideal waveform representing a quadrature component. The apparatus according to claim 19, wherein the software performs the steps of determining a time interval between a plurality of samples of a signal waveform, and counting a number of samples between a plurality of zero crossings. of the signal waveform. The apparatus according to claim 19, wherein the software further performs the step of determining an angle of the signal of the ideal frequency within the waveform of the input signal with respect to the waveform of reference. 22. The apparatus according to claim 19, wherein the software further performs the steps of: multiplying the waveform of the input signal by the ideal waveform in phase to produce a product in phase for each sample of a plurality of samples in a line cycle, for at least one cycle of line; add the product in phase for each sample to an in-phase adder accumulator, to produce a sum-in-phase value; multiplying the waveform of the input signal by the ideal quadrature waveform, to produce a quadrature product for each sample of the plurality of samples in a line cycle, for the plurality of line cycles; and add the product in quadrature for each sample to a quadrature summing accumulator, to produce a quadrature sum value. 23. The apparatus according to claim 22, wherein the software further performs the step of determining a quantity in phase and a quantity in quadrature. The apparatus according to claim 23, wherein the software further performs the step of counting a number of samples in the plurality of line cycles to determine a sample count, wherein the amount in phase = the sum value in phase / the sample count; and the quantity in quadrature = the value of sum in quadrature / the sample count. 25. The apparatus according to claim 23, wherein the magnitude and angle of the signal of the ideal frequency within the waveform of the input signal respond to the quantity in phase and the quantity in quadrature. 26. The apparatus according to claim 25, wherein the software further performs the step of determining a magnitude of the ideal frequency by means of a square root of the sum of the squares of the quantities in phase and in quadrature, multiplied by a factor of scale that is a function of the RMS value of one of the ideal waveforms. 27. The apparatus according to claim 25, wherein the software determines the angle according to the table: Sign of the can- Sign of the can- Calculation of angle in phase tidad in cua- (in degrees) dratura + + Arctan (quadrature / in phase) + 0o + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° + - Arctan (quadrature / in phase) + 360 ° 28. A method for measuring the frequency-dependent electrical parameters by means of an energy meter in an electrical system that provides electrical energy having a variable frequency, which comprises the steps of : select a reference waveform that has a positive zero crossing; synchronize two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; get a waveform of the input signal; and determining a magnitude of a signal of the ideal frequency within the waveform of the input signal, wherein the two ideal waveforms are approximately 90 degrees out of phase with each other, representing an ideal waveform one component in phase, and the other ideal waveform representing a quadrature component. 29. The method according to claim 28, further comprising the step of determining an angle of the signal of the ideal frequency within the waveform of the input signal with respect to the reference waveform. 30. The method according to claim 28, further comprising the steps of: multiplying the waveform of the input signal by the ideal waveform in phase to produce a product in phase for each sample of a plurality of samples in a line cycle, for at least one line cycle; add the product in phase for each sample to an in-phase adder accumulator, to produce a sum-in-phase value; multiply the waveform of the signal input by the ideal quadrature waveform to produce a quadrature product for each sample of the plurality of samples in a line cycle, for the plurality of line cycles; and add the product in quadrature for each sample to a quadrature summing accumulator, to produce a quadrature sum value. 31. The method according to claim 30, which further comprises the step of determining a quantity in phase and a quantity in quadrature. 32. The method according to claim 31, which further comprises the step of counting a number of samples in the plurality of line cycles to determine a sample count, wherein the quantity in phase = the sum value in phase / the sample account; and the quantity in quadrature = the value of sum in quadrature / the sample count. 33. The method according to claim 31, wherein the magnitude and angle of the signal of the ideal frequency within the waveform of the input signal correspond to the quantity in phase and the quantity in quadrature. 34. The method according to claim 33, which further comprises the step of determining a magnitude of the ideal frequency signal by a square root of the sum of the squares of the quantities in phase and in quadrature, multiplied by a scale factor that is a function of the RMS value of one of the ideal waveforms. 35. The method according to claim 33, wherein the step of determining the angle comprises determining this angle according to the table: Sign of the can- Sign of the can- Calculation of angle in phase tidad in cua- ( in degrees) + + Arctan (quadrature / in phase) + 0o + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° + - Arctan (quadrature / in phase) + 360 ° 36. A system for measuring the frequency-dependent electrical parameters by means of an energy meter in an electrical system that provides electric power having a variable frequency by means of a type of service, which comprises: an element for selecting a waveform of reference that has a positive zero crossing; an element for synchronizing two ideal waveforms with the reference waveform, each of the two ideal waveforms having an ideal frequency; an element for obtaining a waveform of the input signal; and an element to determine a magnitude of a signal of the ideal frequency within the waveform of the input signal, wherein the two ideal waveforms are at approximately 90 degrees out of phase with each other, an ideal waveform representing an in-phase component, and the other ideal waveform representing a quadrature component. 37. The system according to claim 36, which further comprises an element for determining an angle of the signal of the ideal frequency within the waveform of the input signal with respect to the reference waveform. 38. The system according to claim 36, which further comprises: an element for multiplying the waveform of the input signal by the ideal waveform in phase to produce a product in phase for each sample of a plurality of samples in a line cycle, for at least one line cycle; an element to add the in-phase product for each sample to an in-phase summing accumulator to produce a sum-in-phase value; an element to multiply the waveform of the input signal by the ideal quadrature waveform, to produce a product in quadrature for each sample of the plurality of samples in a line cycle, for the plurality of line cycles; an element to add the product in quadrature for each sample to a quadrature summing accumulator, to produce a quadrature sum value. 39. The system according to claim 38, which further comprises an element for determining a quantity in phase and a quantity in quadrature. 40. The system according to claim 39, which further comprises an element for counting a number of samples in the plurality of line cycles to determine a sample count, wherein the quantity in phase = the sum value in phase / the sample count; and the quantity in quadrature = the value of sum in quadrature / the sample count. 41. The system according to claim 39, wherein the magnitude and angle of the signal of the ideal frequency within the waveform of the input signal, respond to the quantity in phase and the quantity in quadrature. 42. The system according to claim 41, which further comprises an element for determining a magnitude of the ideal frequency by means of a square root of the sum of the squares of the quantities in phase and in quadrature, multiplied by a scale factor which is a function of the RMS value of one of the ideal waveforms. 43. The system according to claim 41, wherein the element for determining the angle comprises an element for determining this angle according to the table: Sign of the can- Sign of the can- Calculation of angle in the phase cua- (in degrees) dratura + + Arctan (quadrature / in phase) + 0o + Arctan (quadrature / in phase) + 180 ° Arctan (quadrature / in phase) + 180 ° + - Arctan (quadrature / in phase) + 360 °