A METHOD OF DETECTING A PARTIAL DISCHARGE SIGNAL

§103 §112

DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Under 35 USC § 101 Although claim 1 recites mathematical concepts, including recursive calculations of the mean and variance of a filtered electrical signal and comparison of the calculated variance with a specified threshold, claim 1 also recites additional elements such as obtaining a measured broadband analog signal from an electrical network, converting the analog signal into a digital signal; band-pass filtering the digital signal to remove components unrelated to partial discharge, and detecting the presence of a partial discharge based on the calculated variance. These limitations, considered as an ordered combination, integrate the mathematical concepts into a practical application involving the detection of physical electrical discharge events. The claimed method applies the particular signal-processing technique to suppress unwanted signal components while preserving information associated with partial discharge, thereby improving the detection of electrical insulation abnormalities. The specification supports this technological improvement in ¶¶ [0019] and [0059] (see Publication associated with the present invention US 2024/0410930). The inclusion of these additional elements integrates the identified judicial exception into a practical application that effects a meaningful way beyond generally linking the use of the judicial exception to a particular technological environment, such that the claim as a whole is more than a drafting effort designed to monopolize the exception. Therefore, claims 1-7 are considered eligible under 35 U.S.C. § 101. Claim Objections Claim 1 is objected to because of the following informalities: In claim 1, line 5, change “the detection device” to -the measuring device-. In claim 1, line 21, change “at time k (V)” to -at time k. Claim 1 recites “loading the measured broad-spectrum analog signal” in line 7. There is insufficient antecedent basis for this limitation in the claim. Appropriate correction is required. Claim 4 recites “the search for the start” in line 3. There is insufficient antecedent basis for this limitation in the claim. Appropriate correction is required. Claim 7 recites “the phase in the basic harmonic sinusoid of the voltage in the electrical network” in lines 3-4. There is insufficient antecedent basis for this limitation in the claim. Appropriate correction is required. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-7 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Claim 1 recites “initializing the variables in the detection device, and loading the parameters Nvar, lag_max, dead_max”. However, claim 1 does not identify the functions of these parameters or specify their relationship to the subsequently recited steps of measuring, filtering, calculating a mean and variance, and detecting a partial discharge. In particular, none of the three parameters is referenced in the recited mean or variance calculations or in the threshold comparison used to determine the presence of partial discharge, Consequently, it is unclear whether the recited parameters merely represent independently loaded values or whether they are intended to control or otherwise affect the claimed partial-discharge detection operation. The claim therefore fails to clearly define the intended relationship between the parameter-loading step and the remaining method steps, raising uncertainty regarding the scope of the claimed method. Applicant is required to clarify the claimed subject matter consistent with the original disclosure. Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 1 and 2 are rejected under 35 U.S.C. 103 as being unpatentable over lorkyase et al. (NPL: “RF-based location of partial discharge sources using received signal features” (2019) in view of Kuper et al. (Pub. No. US 2017/0242078) (hereinafter Kuper) and further in view of Taleb et al. (Pub. No. US 2011/0046965) (hereinafter Taleb). As per claim 1, Regarding the limitation of measuring a broadband analog signal from an electrical network, converting the measured analog signal into a digital signal, and bad-pass filtering the digital signal, lorkyase teaches acquiring radio-frequency signals generated by partial-discharge activity using three monopole antenna connected to a high-speed multichannel oscilloscope having bandwidth of up to 9 GHz, wherein the received RF signals are sampled at 2 GSa/s (see Section 2.1, “data acquisition”). The disclosed sampling of the received analog RF signals by the oscilloscope necessarily involves converting the analog measurements into digital samples for subsequent signal processing. lorkyase further teaches designing two band-pass filters corresponding to frequency-response peaks of the receiving antennas to extract additional information from the partial-discharge signals (see Section 2.2. “Feature generation and selection”). Accordingly, lorkyase teaches or necessarily implies converting received analog partial-discharge signals into digital signals and processing the sampled signals using band-pass filtering. However, lorkyase fails to explicitly disclose the particular recursive mean and variance calculations recited in claim 1. Kuper, however, teaches a mean of electrical-system parameters using a previously calculated mean and a current measurement (see ¶ [0067], equation (32)), according to: µk = k - 1 k µk-1 + 1 k Rj(k). Kuper further teaches calculating a current variance using a previously calculated variance and the squared difference between a current measurement and the calculated mean (see ¶ [0067], equation (32)), according to:                         σ k 2 = k - 2 k - 1 σ k - 1 2 + k ( k - 1 ) 2 [ R j k -   µ k ] 2 µ k . Accordingly, Kuper teaches the recursive structure of the claimed mean and variance calculations. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to modify the partial-discharge signal-processing technique lorkyase to employ the recursive mean and variance estimation taught by Kuper because lorkyase identifies variance using a previously calculated estimate and squared deviation of a current measurement from its mean (see ¶ [0067]), thereby enabling continuous estimation of partial-discharge signal variability while reducing the need to repeatedly process stored measurements. However, Kuper employs sample-count-dependent coefficients rather than the forgetting factor coefficients λ and 1 – λ recited in claim 1. Taleb, however, teaches calculating a long-term power statistic using a first-order infinite response filter according to: P l t (i) =α   l t (i - 1) + (1 – α) P s t (i). Where α is explicitly identified as a forgetting factor (see]) ¶ [0056. Thus Taleb, weighting a previously calculated statistical quantity by α and a current contribution by (1 – α). Further teaches detecting a transient when the ratio of short-term power to previously calculated long-term power exceeds a threshold (see ¶ [0057]). Accordingly, Taleb establishes that complementary forgetting factor coefficients were known for recursively updating signal-power estimate used in transient detection. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to modify the recursive mean and variance calculations of Kuper using the complementary forgetting factor coefficients taught by Taleb because Taleb teaches that first-order IIR filter can update a signal statistic using a previous estimate weighed by α and a current contribution weighted by (1 – α) for transient detection (see ¶ [0056]), thereby emphasizing recent signal measurements and reducing the influence of older measurements when monitoring changes in partial-discharge signal variability. The resulting modification would apply a known recursive weighting technique to the recursive variance estimator of Kuper for its established purpose of tracking changing signal characteristics. It would additionally have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to compare the resulting recursive variance with a predetermined threshold to detect a partial discharge because lorkyase teaches that variance is a characteristic of partial-discharge signals (see Page 29, Table 1 and Fig. 5(a)) and Taleb, teaches using a threshold comparison to detect transient changes in signal characteristic (see ¶ [0057]), thereby providing a computationally efficient indicator of abnormal partial-discharge activity. Regarding the limitations of initializing variables and loading the parameters Nvar, lag_max, and dead_max, it would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to initialize variables and load predetermined operating parameters into the partial-discharge detection system of lorkyase, as modified by Kuper and Taleb, because initialization and parameter loading are routine preparatory operations in digital signal-processing systems, thereby establishing operating conditions for executing the signal-processing algorithm. Furthermore, claim 1 does not require that the loaded parameters Nvar, lg_max, and dead_max be subsequently used in calculating the recursive mean, calculating the recursive variance, or comparing the variance with a threshold. Accordingly, the claimed loading operations do not impose a further functional relationship between these particular parameters and the subsequently recited partial-discharge detection operations. As per claim 2, the combination of lorkyase, Kuper, and Taleb teaches the system as stated above. Kuper teaches recursively estimating a mean and variance from previously calculated estimates and current measurements (see ¶ [0067]. Equation (32)). Taleb teaches an IIR statistical update using a prior value and a forgetting factor, P l t (i) =α   l t (i - 1) + (1 – α) P s t (i) (see ¶ [0056]). These disclosures establish recursive state variables that require defined starting values before the first update. Neither cited passage, However, explicitly require zero initialization of both the mean and variance. However, it would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to select zero as the initial value for the recursive mean and variance estimates when implementing the combined signal-processing technique, because zero is a straightforward defined starting state for accumulators before samples are processed, thereby allowing the recursive updates to begin without requiring previously stored mean and variance values. Selecting this initial condition would have been a predictable implementation choice for the recursive estimator, rather than a change to the underlying variance-detection principle. Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over lorkyase in view of Kuper and further in view of Taleb and Canac et al. (NPL: “Algorithm for Reliable Detection of Pulse Onsets in Cerebral Blood Flow Velocity Signals) (2019) (hereinafter Canac). As per claim 4, the combination of lorkyase, Kuper, and Taleb teaches the system as stated above. lorkyase, as modified by Kuper and Taleb, teaches detecting partial-discharge activity using statistical characteristics of measured signals, including variance (see Lorkyase, Section 2.2., Table 1; Kuper ¶ [0067]; and Taleb ¶¶ [0056]-[0057]). However, the combination fails to explicitly disclose terminating a search for the beginning of a detected discharge after a predetermined number of samples have elapsed from the moment of discharge detection. Canac, however, teaches a signal-processing method for identifying pulse onsets in measured signals. In particular, Canac teaches identifying threshold crossings and establishing search windows for locating pulse beginnings (see Section 3.3), identifying pulse onsets by examining candidate valleys within the established search windows (see Section 3.4), and performing a threshold-search operation that continues until a threshold crossing occurs or the end of the data segment is reached (see Section 3.5.2, step 4). Thus, Canac teaches restricting pulse-onset determination to a bounded search interval and terminating a search upon reaching a defined boundary. It would have been obvious to one having ordinary skill in the art before the effective filling date of the claimed invention to modify the partial-discharge detection method of lorkyase, as modified by Kuper and Taleb, to employ a bounded pulse-onset search as taught by Canac, because Canac demonstrates that limiting an onset-search operation to a predetermined observation interval allows a signal-processing system to identify the beginning of a detected pulse without continuing the search indefinitely, thereby reducing unnecessary signal processing and providing a defined termination condition for the discharge-onset search. Furthermore, where the signal is digitally sampled at a known sampling frequency, the duration of the bounded search interval may be expressed as a predetermined number of samples. Accordingly, it would have been obvious implementation of choice to establish a maximum sample count, such as the claimed dead_max, and terminate the onset-search operation upon expiration of that count, thereby providing a sample-based termination condition for the onset-search procedure. Allowable Subject Matter Claims 3 and 5-7 are objected to as being dependent upon a rejected base claim but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims and overcoming the objections and the 35 U.S.C. § 112(b) rejection made above. Regarding claim 3, none of the prior art of record teaches or fairly suggests a method of detecting a partial discharge signal, in particular a method of detecting a partial discharge signal from a signal measured by a measuring device at at least one point of the electrical network, comprising: the proportion of the variance value of 02 at time k and at time k-Nvar is determined such that: PNG media_image1.png 70 252 media_image1.png Greyscale where Nvar is an selectable parameter that indicates the number of variance samples by which the denominator of the above fraction is shifted from the numerator, and the time of the maximum k_max is stored in memory in a horizon shorter than lag_max from the current time k, and the start of the discharge id_beg is determined such that: id_beg =k_max - Nvar, whereas if no new maximum is determined in the following dead_max samples, the moment id_beg is considered the start of the discharge, and if a new maximum of the function Δ σ 2 2 is found in the following dead-max samples, then this new moment id_beg is considered to be the start of the discharge, and the information about start of discharge idbeg is updated in the memory, in combination with the rest of the claim limitations as claimed and defined by the applicant. Regarding claim 5, none of the prior art of record teaches or fairly suggests a method of detecting a partial discharge signal, in particular a method of detecting a partial discharge signal from a signal measured by a measuring device at at least one point of the electrical network, comprising: in the case of the presence of a partial discharge, the end id_end of the partial discharge is further determined so that the moment at which the value of the criterion function falls below 1.1 times the value of the criterion function at the beginning of the partial discharge it is declared as the end of the partial discharge, such that: PNG media_image2.png 66 468 media_image2.png Greyscale PNG media_image3.png 330 676 media_image3.png Greyscale , in combination with the rest of the claim limitations as claimed and defined by the applicant. Regarding claim 6, none of the prior art of record teaches or fairly suggests a method of detecting a partial discharge signal, in particular a method of detecting a partial discharge signal from a signal measured by a measuring device at at least one point of the electrical network, comprising: wherein in the case of the presence of a partial discharge, the total charge is further determined such that: PNG media_image4.png 212 682 media_image4.png Greyscale , in combination with the rest of the claim limitations as claimed and defined by the applicant. Regarding claim 7, none of the prior art of record teaches or fairly suggests a method of detecting a partial discharge signal, in particular a method of detecting a partial discharge signal from a signal measured by a measuring device at at least one point of the electrical network, comprising: wherein in the case of the presence of a partial discharge, the phase in the basic harmonic sinusoid of the voltage in the electrical network is further determined such that: PNG media_image5.png 278 744 media_image5.png Greyscale , where the duration of the last full period T is used as the AC voltage period and to is the start time of the current voltage period, in combination with the rest of the claim limitations as claimed and defined by the applicant. Prior art The prior art made record and not relied upon is considered pertinent to applicant’s disclosure: Andle et al. [‘760] discloses a method of detecting a partial discharge in an electrical asset includes sensing of a discharge current in the electrical asset using a transducer and responsively providing a transducer output; processing the transducer output by comparing the transducer output to a baseline; calculating an accumulated amount by which the transducer output exceeds the baseline; decreasing the accumulated amount with time; detecting partial discharge in the electrical asset based upon the accumulated amount; and providing an output related to detected partial discharge. A partial discharge detection system for detecting a partial discharge in an electrical asset includes a transducer configured to receive a signal from the electrical asset generated due to an occurrence of partial discharging in the electrical asset and responsively providing a transducer output. Processing circuitry compares the transducer output to a baseline, calculates an accumulated amount by which the transducer output exceeds the baseline, decreases the accumulated amount with time, and detects partial discharge in the electrical asset based upon the accumulated amount. Output circuitry provides an output related to detected partial discharge. Fournier et al. [‘420] discloses an apparatus for detecting, localizing and interpreting a partial discharge occurring in a partial discharge site along an electrical equipment, comprising: two measurement probes and a synchronization probe installable along the electrical equipment so that pulses travelling in the electrical equipment are detectable by the measurement probes and a phase angle in the electrical equipment is detectable by the synchronization probe; a control unit connecting to the measurement probes for receiving signals representative of the detected pulses, and connecting to the synchronization probe for acquiring a signal representative of the detected phase angle, the control unit having a circuit for selective conditioning of the received signals; and a digital processing unit connecting to the control unit for acquiring the signals after selective conditioning as a function of the detected phase angle and driving the control unit, the digital processing unit having a correlation measuring module for measuring correlation of the acquired signals, a module for performing a time-frequency distribution of at least one of the acquired signals, a form factor estimating module for estimating a form factor derived from the time-frequency distribution, and a diagnosis module responsive to results generated by the correlation measuring and form factor estimating modules for generating a diagnosis indicative of a detection of a partial discharge and of its localization along the electrical equipment. Contact information Any inquiry concerning this communication or earlier communications from the examiner should be directed to MOHAMED CHARIOUI whose telephone number is (571)272-2213. The examiner can normally be reached Monday through Friday, from 9 am to 6 pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Andrew Schechter can be reached on (571) 272-2302. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). Mohamed Charioui /MOHAMED CHARIOUI/Primary Examiner, Art Unit 2857