A-base revenue meter with power quality features
First Claim
1. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
- a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
one or more sensors coupled with said electric circuit and operative to sense one or more power parameters in said electric circuit and generate one or more analog signals indicative of said power parameters;
at least one analog to digital converter coupled with said sensors and operative to convert said analog signals to one or more digital samples; and
a detector coupled with said analog to digital converter and operative to compare each of said digital samples to a threshold and indicate a power quality event when said digital sample deviates from said threshold.
1 Assignment
0 Petitions
Accused Products
Abstract
Power quality detection, monitoring, reporting, recording and communication in a revenue accuracy electrical power meter is disclosed. Transient events are detected by monitoring the wave shape of the electrical power and comparing deviations to a known threshold. Sags and Swells are detected by computing root mean square value over a rolling window and comparing the computed value with a known threshold. Harmonic frequencies and symmetrical components are quantified by a known algorithm and compared with a known threshold. Incoming waveforms are stored to memory. All recorded and computed data is moved to non-volatile storage via direct memory access transfer in the event that a power quality event jeopardizes the operating power of the meter. Further, the meter provides a power supply utilizing high and low capacitive storage banks to supply sufficient energy to survive short duration power quality events which jeopardize the meter'"'"'s operating power.
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Citations
85 Claims
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1. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
one or more sensors coupled with said electric circuit and operative to sense one or more power parameters in said electric circuit and generate one or more analog signals indicative of said power parameters;
at least one analog to digital converter coupled with said sensors and operative to convert said analog signals to one or more digital samples; and
a detector coupled with said analog to digital converter and operative to compare each of said digital samples to a threshold and indicate a power quality event when said digital sample deviates from said threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said terminal cover;
a sensor coupled with said electric circuit and operative to sense a voltage in said electric circuit and generate an analog signal indicative of said voltage;
an analog to digital converter coupled with said sensor and operative to convert said analog signal to one or more digital samples; and
a detector coupled with said analog to digital converter and operative to compare each of said digital samples to a threshold and indicate a transient event when said digital sample exceeds said threshold. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
a sensor coupled with said electric circuit and operative to sense the voltage in said electric circuit and generate an analog signal indicative of said voltage, said voltage having a wave shape;
an analog to digital converter coupled with said sensor and operative to convert said analog signal to one or more digital samples;
a memory coupled with said analog to digital converter and operative to receive and store at least 2 cycles worth of said one or more digital samples; and
a detector coupled with said memory and operative to compare a first of said digital samples to a second of said digital samples and calculate a difference, said second digital sample being non-consecutive with said first digital sample, said detector further operative to compare said difference to a threshold and indicate a deviation in said wave shape when said difference exceeds said threshold. - View Dependent Claims (27, 28, 29, 30, 31)
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32. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
a first sensor coupled with said electric circuit and operative to sense the voltage in said electric circuit and generate a first analog signal indicative of said voltage;
a second sensor coupled with said electric circuit and operative to sense the current in said electric circuit and generate a second analog signal indicative of said current;
an analog to digital converter coupled with said first and second sensors and operative to convert said first and second analog signals to one or more digital samples a memory coupled with said analog to digital converter and operative to receive and store said digital samples; and
a calculator coupled with said memory and operative to compute one or more harmonic frequencies of said voltage and said current from said stored digital samples. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said electric circuit comprising at least one phase, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
one or more voltage sensors coupled with each of said at least one phase of said electric circuit and operative to sense the voltage in each of said at least one phase and generate an analog signal indicative of said voltage;
one or more current sensors coupled with each of said at least one phase of said electric circuit and operative to sense the current in each of said at least one phase and generate an analog signal indicative of said current;
at least one analog to digital converter coupled with said one or more voltage sensors and said one or more current sensors and operative to convert said analog signals to one or more digital samples at a rate of at least 64 samples per cycle;
a memory coupled with said analog to digital converter and operative to receive and store said one or more digital samples; and
a processor coupled with said memory and operative to compute one or more fundamental voltage vectors from the magnitude and phase angle of the fundamental frequency of each of said voltage and said current and further operative to compute the zero, positive and negative sequence voltages by performing a vector addition of said one or more fundamental voltage vectors. - View Dependent Claims (45, 46, 47, 48, 49, 50)
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51. In an A base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said electric circuit comprising at least one phase, a method of computing symmetrical components comprising:
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providing an A base revenue meter including a display, terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit, a meter cover operative to enclose said meter and said display, a terminal cover for covering said terminals, a first seal connected with said meter cover and operative to prevent removal of said meter cover, a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
sensing the voltages in each of said at least one phase and generating analog signals indicative thereof;
converting said analog signals to one or more digital samples at a rate of at least 64 samples per cycle;
storing said digital samples in a memory;
computing one or more fundamental voltage vectors from the magnitude and angle of the fundamental frequency of each of the sensed voltages from said stored digital samples; and
performing a vector addition of said one or more fundamental voltage vectors to compute the zero sequence voltage. - View Dependent Claims (52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
shifting a first of said one or more fundamental voltage vectors by plus 120 degrees from a first starting point;
shifting a second of said one or more fundamental voltage vectors by minus 120 degrees from a second starting point;
performing a vector addition of said first, said second and remaining fundamental voltage vectors;
computing the positive voltage sequence;
shifting said first of said one more fundamental voltage vectors by minus 120 degrees from said first starting point;
shifting said second of said one or more fundamental voltage vectors by plus 120 degrees from said second starting point;
performing a vector addition of said first, said second and remaining fundamental voltage vectors; and
computing the negative voltage sequence.
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55. The method of claim 54 further comprising displaying said one or more fundamental voltage vectors.
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56. The method of claim 54 further comprising:
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comparing said zero, positive and negative sequence voltages to a threshold; and
indicating when said voltages exceed said threshold.
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57. The method of claim 56 further comprising triggering a waveform recorder when said voltages exceed said threshold.
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58. The method of claim 51 further comprising:
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sensing the currents in each of said at least one phase and generating analog signals indicative thereof;
converting said analog signals to one or more digital samples;
storing said digital samples in a memory;
computing one or more fundamental current vectors from the magnitude and angle of the fundamental frequency of each of the sensed currents from said stored digital samples;
performing a vector addition of said one or more fundamental voltage vectors; and
computing the zero sequence current.
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59. The method of claim 58 further comprising:
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shifting a first of said one or more fundamental current vectors by plus 120 degrees from a first starting point;
shifting a second of said one or more fundamental current vectors by minus 120 degrees from a second starting point;
performing a vector addition of said first, said second and remaining fundamental current vectors;
computing the positive current sequence;
shifting said first of said one more fundamental current vectors by minus 120 degrees from said first starting point;
shifting said second of said one or more fundamental current vectors by plus 120 degrees from said second starting point;
performing a vector addition of said first, said second and remaining fundamental current vectors; and
computing the negative current sequence.
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60. The method of claim 59 further comprising displaying said one or more fundamental current vectors.
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61. The method of claim 59 further comprising:
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comparing said zero, positive and negative sequence currents to a threshold; and
indicating when said currents exceed said threshold.
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62. The method of claim 61 further comprising triggering a waveform recorder when said currents exceed said threshold.
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63. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
a sensor coupled with said electric circuit and operative to sense a power parameter in said electric circuit and generate an analog signal indicative of said power parameter;
an analog to digital converter coupled with said sensor and operative to convert said analog signal to one or more digital samples at a rate of at least 64 samples per cycle;
a first memory coupled with said analog to digital converter and operative to receive and store said one or more digital samples;
a second memory coupled with said first memory;
a power quality event detector coupled with said analog to digital converter and operative to detect a power quality event and generate a trigger signal;
a holdoff timer coupled with said detector and operative to receive, delay and re-transmit said trigger signal; and
a memory preservation mechanism coupled with said first memory, said second memory and said holdoff timer and operative to preserve the contents of said first memory using said second memory upon receipt of said trigger signal from said holdoff timer. - View Dependent Claims (64, 65, 66, 67, 68, 69, 70, 71)
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72. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
a first power supply coupled with said electric circuit and operative to provide power to said meter from said electric circuit under normal operating conditions;
a second power supply operative to provide power to said meter when a power quality event occurs on said electric circuit, said second power supply including;
at least one first capacitor coupled with said electric circuit and operative to store electrical energy from said electric circuit; and
at least one second capacitor coupled with said at least one first capacitor and said meter and operative to store electrical energy from said electric circuit;
said first and second capacitors further operative to provide said energy to said meter when said power quality event occurs. - View Dependent Claims (73)
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74. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover;
a switching regulator coupled with said electric circuit and said meter and operative to convert said high voltage electrical energy to low voltage electrical energy;
a power supply coupled between said electric circuit and said switching regulator and operative to store said high voltage electrical energy and provide power to said meter when a power quality event occurs on said electric circuit. - View Dependent Claims (75)
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76. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover; and
a power supply coupled with said electric circuit and said meter and operative to store energy from said electric circuit and provide said energy to said meter when a power quality event occurs on said electric circuit, said power supply including;
a high voltage portion coupled with said electric circuit and a low voltage portion coupled with said high voltage portion and said meter; and
a processor coupled with said high voltage portion and operative to monitor said power supply and signal said meter when said stored energy runs low. - View Dependent Claims (77)
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78. An A-base revenue meter for measuring the delivery of electrical energy from an energy supplier to a consumer through an electric circuit, said meter comprising:
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a display;
terminals disposed on a bottom side of said meter for coupling said meter with said electric circuit;
a meter cover operative to enclose said meter and said display;
a terminal cover for covering said terminals;
a first seal connected with said meter cover and operative to prevent removal of said meter cover;
a second seal connected with said terminal cover and operative to prevent removal of said terminal cover; and
a power supply coupled with said electric circuit and said meter and operative to store energy from said electric circuit and provide said energy to said meter when a power quality event occurs on said electric circuit, said power supply including;
a rectification circuit coupled with said electric circuit and operative to receive AC electric energy from said electric circuit and convert said AC electric energy to high voltage DC electric energy;
a charge control circuit coupled with said rectification circuit;
a first energy store coupled with said charge control circuit and operative to receive and store said high voltage DC electric energy from said rectification circuit at a rate controlled by said charge control circuit, said first energy store further operative to provide said stored high voltage DC electric energy to said meter when a power quality event occurs on said electric circuit; and
a switching regulator coupled with said rectification circuit and said first energy store, said switching regulator operative to receive said high voltage DC electric energy from said rectification circuit and said first energy store, said switching regulator further operative to covert said high voltage DC electric energy to low voltage DC electric energy and provide said low voltage DC electric energy to said meter. - View Dependent Claims (79, 80, 81, 82, 83, 84, 85)
a current limiter operative to limit inrush current to said meter; and
a bypass operative to bypass said current limiter when said at least one energy store is charged.
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84. The revenue meter of claim 78, further comprising a second energy store coupled with said rectification circuit, said charge control circuit and said switching regulator, said second energy store having a faster charging time than said first energy store and operative to provide stored high voltage DC electric energy to said switching regulator before said first energy store is charged.
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85. The revenue meter of claim 84, wherein said second energy store comprises at least one capacitor.
Specification