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 .
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 10-16 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.
In claim 10, “the housing” lacks antecedent basis, rending the scope of the claim unclear. Claims 11-16 are rejected under 35 U.S.C. 112(b) by virtue of their dependence from claim 10.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 1-8, 10-17 and 20 are rejected under 35 U.S.C. 103 as being unpatentable over US 2017/0184458 to Jeffries et al. (Jeffries).
Regarding claim 1, Jeffries discloses a system for temperature compensation in transformer current metering, the system comprising:
a current transformer (CT) assembly comprising:
a CT configured to generate a current signal representative of a current in a conductor passing through a core of the CT (Jeffries, e.g., Fig. 2 and paragraphs 23-25, CT 46);
a temperature sensor associated with the CTmeasurement circuit 54, consisting of a buffer 58 and an analogue to digital converter (ADC) 62, a memory 34 for storing reference data, historic data and algorithms 38 and one of more processors 42; reference data can include, but is not limited to, CT design/material data, lookup tables, resistance/temperature relationships and verified test data; historic data can include, but is not limited to, past resistance data, voltage data, temperature data, expected temperatures based on sensed currents, and diagnostic results; the DC current circuit 50 can be controlled by the measuring/monitoring device 30 such that the injected DC current can be turned off, increased or decreased as required to increase measurement accuracy; the processor 42 uses the algorithms 38, reference data and measured data to determine the temperature of the secondary winding 26; using the superposition electrical theorem, the ADC 62 can measure current sensor output current burden resistance RB and current source (burden resistance RB I current sensor 46 winding 26 resistance); knowing the burden resistance RB and the output of the current source 50, the resistance of the current sensor 46 winding 26 can be calculated; alternatively, the resistance of the secondary winding 26 can be calculated from information about the voltage induced by the DC current circuit 50; once the resistance of the secondary winding 26 is known the temperature can be determined based on characteristics of the CT 46 design (relationships between resistance and temperature based on materials used in the CT 46 and stored in memory 34); accordingly, Jeffries disclose that the secondary winding 26 can be selectively configured for use as a resistance temperature detector in order to determine an operating temperature of the CT 46);
a trip unit communicatively coupled to the CT, the trip unit comprising:
a processor (Jeffries, e.g., Fig. 2 and paragraphs 23-25, processor 42); and
a memory coupled to the processor (Jeffries, e.g., Fig. 2 and paragraphs 23-25, processor 42), the memory storing computer-executable instructions (Jeffries, e.g., Fig. 2 and paragraphs 23-25, memory 34 for storing reference data, historic data and algorithms 38) that, when executed by the processor, configure the trip unit for:
receiving a temperature measurement from the temperature sensor, the temperature measurement indicative of a temperature of the CT (Jeffries, e.g., Fig. 2 and paragraphs 23-25, processor 42 uses the algorithms 38, reference data and measured data to determine the temperature of the secondary winding 26; once the resistance of the secondary winding 26 is known the temperature can be determined based on characteristics of the CT 46 design (relationships between resistance and temperature based on materials used in the CT 46 and stored in memory 34); a resistance/temperature relationship table created by measuring secondary winding 26 resistances at verified temperatures can also be used to determine the temperature of secondary winding 26);
receiving the current signal from the CT (Jeffries, e.g., Fig. 2 and paragraphs 23-25, once the induced voltage, resistance and temperature of the secondary winding 26 have been determined and stored in memory 34, the processor 42 can evaluate the accuracy of the induced current signal from the secondary winding 26 by comparing the determined secondary winding 26 temperature with previously determined secondary winding 26 temperatures known to produce CT sensing errors and compensate accordingly for any temperature related error); and
calculating a temperature compensated current measurement based on the temperature measurement and the current signal (Jeffries, e.g., Fig. 2 and paragraphs 23-25, once the induced voltage, resistance and temperature of the secondary winding 26 have been determined and stored in memory 34, the processor 42 can evaluate the accuracy of the induced current signal from the secondary winding 26 by comparing the determined secondary winding 26 temperature with previously determined secondary winding 26 temperatures known to produce CT sensing errors and compensate accordingly for any temperature related error; compensating can be accomplished by comparing the sensed current believed to be in error with historic resistance/temperature data or verified resistance/temperature test data and other stored characteristics of the CT 46 to determining a correction factor that can be used to compensate for the temperature related current sensing error; the ability to compensate for temperature related errors permits the CT 46 to maintain dependable accurate current readings).
The portions of Jeffries referenced above are not relied upon as explicitly disclosing a housing enclosing the CT, and the temperature sensor enclosed within the housing. Jeffries nonetheless discloses that providing an enclosure for a CT is known (Jeffries, e.g., paragraph 3, in some instances the CTs are installed inside small enclosures). It 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 to modify Jeffries’ arrangement of Fig. 2 to include a housing enclosing the CT, with the temperature sensor being enclosed within the housing. In this way, protection of the CT from dirt/debris, as well as protection from mechanical damage, can be realized.
Regarding claim 2, Jeffries is not relied upon as explicitly disclosing wherein the trip unit comprises a display and wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: displaying, on the display of the trip unit, the temperature compensated current measurement. The examiner takes Official notice of the fact that the use of screens, e.g., LED displays, in connection with processor-based instrumentation and control devices was well-known and conventional before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to enable local viewing of monitored parameters. It 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 to modify Jeffries’ trip unit of Fig. 2 to include a display and wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: displaying, on the display of the trip unit, the temperature compensated current measurement. In this way, the temperature compensated current measurement of Jeffries’ CT can be observed locally by service personnel.
Regarding claim 3, Jeffries is not relied upon as explicitly disclosing wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: alerting a high heat status in response to the temperature measurement exceeding a predetermined threshold (Jeffries, e.g., Fig. 4 and paragraph 27, the processor 42 can compare, at step 130, the determined secondary temperature with a previously determined secondary temperature expected for the current being sensed by the CT 46; if the determined secondary temperature exceeds the expected secondary temperature a possible loose electrical connection can be reported to the monitoring device 30 at step 135). Further, it 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 to modify Jeffries that excessive secondary temperature is alerted on the display of the trip unit. In this way, excessive secondary temperature can be indicated locally to service personnel so that remedial action can be taken.
Regarding claim 4, the portions of Jeffries referenced above in connection with the rejection of claim 1 are not relied upon as explicitly disclosing wherein the system further comprises a breaker communicatively coupled to the trip unit, the breaker configured to receive a trip signal from the trip unit to prevent a flow of current in response thereto, and wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: sending, by the trip unit, the trip signal to the breaker in response to the temperature compensated current measurement exceeding a predetermined threshold. Jeffries nonetheless discloses that in a typical CT arrangement such as shown in Fig. 1, the secondary winding 26 is connected to a measuring/monitoring device 30, which could be a protection device such as a circuit breaker, overload relay or other device capable of interpreting an induced current signal received from in the secondary winding 26. Jeffries discloses that if the induced current signal from the secondary winding 26 indicates that current in the primary winding 14 has exceeded a predetermined level the monitoring device 30 can initiate an interruption of current flow in the primary winding 14. Jeffries discloses that in more sophisticated protection devices the monitoring device 30 can include a memory 34 for storing algorithms 38 used by at least one processor 42 to interpret the induced current signal from the secondary winding 26, determine if current flow in the primary winding 14 exceeds the predetermined level and initiate the interruption of current flow in the primary winding 14 (Jeffries, e.g., Fig. 1 and paragraph 2). It 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 to modify Jeffries to include a breaker communicatively coupled to the trip unit, the breaker configured to receive a trip signal from the trip unit to prevent a flow of current in response thereto, and wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: sending, by the trip unit, the trip signal to the breaker in response to the temperature compensated current measurement exceeding a predetermined threshold. In this way, in the same manner as disclosed in connection with known circuit breaker arrangements, Jeffries’ trip unit of Fig. 2 can be communicatively coupled to a circuit breaker in order to obtain over-current protection based on Jeffries’ temperature-compensated current readings.
Regarding claim 5, the portions of Jeffries referenced above in connection with the rejection of claim 4 are not relied upon as explicitly disclosing wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: sending, by the trip unit, a second trip signal to the breaker in response to the temperature measurement exceeding a predetermined threshold. Jeffries nonetheless discloses in connection with Fig. 4 that if the determined secondary temperature exceeds the expected secondary temperature a possible loose electrical connection can be reported to the monitoring device 30 at step 135 (Jeffries, e.g., Fig. 4 and paragraph 27). One of ordinary skill in the art will understand that a loose electrical connection represents a potential fire/safety risk, and that a prudent course of action would be to interrupt current flow in the primary winding of the CT until the cause of excessive temperature can be determined. It 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 to modify Jeffries such that the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: sending, by the trip unit, a second trip signal to the breaker in response to the temperature measurement exceeding a predetermined threshold. In this way, any potential fire/safety risk can be mitigated while the cause of the excessive temperature is investigated.
Regarding claim 6, the portions of Jeffries referenced above in connection with the rejection of claim 1 are not relied upon as explicitly disclosing wherein the CT comprises a first CT, the housing comprises a first housing, and the temperature sensor comprises a first temperature sensor configured to provide a first temperature measurement, the system further comprising: a second CT assembly comprising: a second CT configured to generate a second current signal representative of a current in a conductor passing through a core of the second CT; a second housing enclosing the CT; and a second temperature sensor associated with the second CT, the second temperature sensor enclosed within the second housing. The examiner takes Official notice of the fact that the use of multi-phase (e.g., three-phase) power systems were well-known and conventional before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. It 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 to modify Jeffries such that the CT comprises a first CT, the housing comprises a first housing, and the temperature sensor comprises a first temperature sensor configured to provide a first temperature measurement, the system further comprising: a second CT assembly comprising: a second CT configured to generate a second current signal representative of a current in a conductor passing through a core of the second CT; a second housing enclosing the CT; and a second temperature sensor associated with the second CT, the second temperature sensor enclosed within the second housing. In this way, Jeffries’ arrangement of Fig. 2 can be replicated for each phase of a multi-phase power system to provide temperature compensation and protection for each of the phases.
Regarding claim 7, the portions of Jeffries referenced above in connection with the rejection of claim 6 are not relied upon as explicitly disclosing wherein the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: receiving a second temperature measurement from the second temperature sensor, the second temperature measurement indicative of a temperature of the second CT; comparing the first temperature measurement from the first temperature sensor to the second temperature measurement from the second temperature sensor; and generating a temperature imbalance alert in response to an imbalance between the first temperature measurement and the second temperature measurement. One of ordinary skill in the art would nonetheless understand in multi-phase power system such as a three-phase power system that phase currents are ideally equal, and that conditions such as loss of a phase (which is a condition considered by Jeffries, see, e.g., paragraph 25) may increase current in the other phases, thereby increasing conductor temperatures. One of ordinary skill in the art would therefore understand in the application of Jeffries’ arrangement in a three-phase power system that temperature imbalances between the CTs may be indicative of a loss of phase condition. Likewise, one of ordinary skill in the art would understand that arcing conditions in one phase of a three-phase system may result in a temperature imbalance between the CTs. It 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 to modify Jeffries such that the memory stores computer-executable instructions that, when executed by the processor, further configure the trip unit for: receiving a second temperature measurement from the second temperature sensor, the second temperature measurement indicative of a temperature of the second CT; comparing the first temperature measurement from the first temperature sensor to the second temperature measurement from the second temperature sensor; and generating a temperature imbalance alert in response to an imbalance between the first temperature measurement and the second temperature measurement. In this way, possible conditions that one ordinary skill in the art would understand can be associated with temperature imbalances between Jeffries’ CTs when used in a multi-phase power system may be identified for investigation.
Regarding claim 8, Jeffries as applied to claim 1 discloses wherein the temperature sensor comprises at least one of a thermocouple, thermistor, or a resistance temperature detector (see Jeffries as applied to claim 1, Jeffries disclose that the secondary winding 26 can be selectively configured for use as a resistance temperature detector in order to determine an operating temperature of the CT 46).
Claim 10 recites a method for measuring temperature compensated current, the method comprising:
generating a temperature measurement, by a temperature sensor in an assembly of a current transformer (CT), the temperature measurement indicative of a temperature within the housing of the CT, wherein the CT is configured to generate a current signal representative of a current in a conductor passing through a core of the CT;
transmitting, to a trip unit, the current signal generated by the CT and the temperature measurement generated by the temperature sensor; and
calculating, by the trip unit, a temperature compensated current based on the current signal and the temperature measurement,
and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 1.
Claim 11 recites displaying the temperature compensated current on a display of the trip unit and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 2.
Claim 12 recites displaying a high heat status on a display of the trip unit in response to the temperature measurement exceeding a predetermined threshold and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 3.
Claim 13 recites sending, by the trip unit, a trip signal to a breaker in response to the temperature compensated current measurement exceeding a predetermined threshold, the breaker configured to receive the trip signal to prevent a flow of current and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 4.
Claim 14 recites sending, by the trip unit, a second trip signal to the breaker in response to the temperature measurement exceeding a predetermined threshold and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 5.
Claim 15 recites wherein the temperature measurement comprises a first temperature measurement generated by a first temperature sensor in a first assembly of a first CT, the method further comprising: generating a second temperature measurement, by a second temperature sensor in a second assembly of a second CT, the second temperature measurement indicative of a temperature within a second housing of the second CT, wherein the second CT is configured to generate a second current signal representative of a current in a conductor passing through a core of the second CT; transmitting, to a trip unit, the second current signal generated by the second CT and the second temperature measurement generated by the second temperature sensor; comparing the first temperature measurement from the first temperature sensor to the second temperature measurement from the second temperature sensor; and generating a temperature imbalance alert in response to an imbalance between the first temperature measurement and the second temperature measurement and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claims 6-7.
Claim 16 recites calculating, by the trip unit, a second temperature compensated current based on the second current signal and the second temperature measurement and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claims 6-7.
Claim 17 recites a current transformer (CT) assembly comprising:
a CT configured to generate a current signal representative of a current in a conductor passing through a core of the CT;
a housing enclosing the CT; and
a temperature sensor associated with the CT, the temperature sensor enclosed within the housing and configured to generate a temperature measurement indicative of a temperature of the CT and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries for reasons analogous to those discussed above in connection with the rejection of claim 1.
Regarding claim 20, Jeffries discloses wherein the temperature sensor comprises at least one of a thermocouple, thermistor, or a resistance temperature detector (see Jeffries as applied to claim 1, Jeffries disclose that the secondary winding 26 can be selectively configured for use as a resistance temperature detector in order to determine an operating temperature of the CT 46).
Claims 9 and 18-19 are rejected under 35 U.S.C. 103 as being unpatentable over Jeffries in view of US 2012/0062211 to Neal et al. (Neal).
Regarding claim 9, Jeffries as applied to claim 1 discloses wherein the temperature sensor is configured to generate a temperature signal indicative of the temperature of the CT (see Jeffries as applied to claim 1). The portions of Jeffries referenced above in connection with the rejection of claim 1 are not relied upon as explicitly disclosing a printed circuit board assembly (PCBA) on the housing of the CT assembly, the PCBA communicatively coupled to the temperature sensor and having sensor electronics thereon configured to generate the temperature measurement from the temperature signal. Printed circuit board assemblies containing CTs and associated electronics, with the printed circuit board assembly being attached to a housing, are known (Neal, e.g., Fig. 3 and paragraphs 23, 29). The prior art included each element claimed, although not necessarily in a single prior art reference, with the only difference between the claimed invention and the prior art being the lack of actual combination of the elements in a single prior art reference. One of ordinary skill in the art could have combined the elements as claimed by known methods, and that in combination, each element merely performs the same function as it does separately. Moreover, one of ordinary skill in the art would have recognized that the results of the combination were predictable. For these reasons, the recitation of a printed circuit board assembly (PCBA) on the housing of the CT assembly, the PCBA communicatively coupled to the temperature sensor and having sensor electronics thereon configured to generate the temperature measurement from the temperature signal does not patentably define over Jeffries when considered in light of Neal.
Claim 18 recites a printed circuit board assembly (PCBA) enclosed within the housing, the PCBA communicatively coupled to the temperature sensor and having sensor electronics thereon configured to generate the temperature measurement and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries in view of Neal for reasons analogous to those discussed above in connection with the rejection of claim 9.
Claim 19 recites wherein the CT comprises a current sensor, the current sensor communicatively coupled to the PCBA, and wherein the current sensor and the temperature sensor are both on the PCBA and is rejected under 35 U.S.C. 103 as unpatentable over Jeffries in view of Neal for reasons analogous to those discussed above in connection with the rejection of claim 9, recognizing in Jeffries’ arrangement of Fig. 2 that the secondary winding 26 in combination with that circuitry of the measuring/monitoring device 30 that measures a current induced in the secondary winding 26 constitutes a current sensor.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
EP1673842B1 to Reid et al. relates to a combination of a single low-cost current sensor and a small, low-cost microcontroller, designed for use as part of a ground-fault circuit breaker or receptacle device to meet all the requirements of UL 943 while addressing the issues of existing designs; see, e.g., Fig. 1, temperature-sensing circuit 26.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DANIEL R MILLER whose telephone number is (571)270-1964. The examiner can normally be reached 9AM-5PM EST M-F.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Lee Rodak, can be reached at 571-270-5628. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DANIEL R MILLER/Primary Examiner, Art Unit 2858
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