METHOD OF INSTALLED AC VOLTAGE IDENTIFICATION IN CONDUCTOR BY CLOSED HERMETIC CONTACT Russian patent published in 2018 - IPC G01R19/30 G01R31/00 

FIELD: electricity.

SUBSTANCE: method for identifying a steady-state alternating current in a conductor by means of a closing reed switch and a microprocessor, in which, in the laboratory, the first closing reed switch is placed in the inductor (CI) so that their longitudinal axes coincide, then alternating current is applied to the CI, gradually increasing it to current , where is the smallest current in the CI at which the reed switches (contact closure) occurs, is the current amplitude, its value is measured, the time of the closed state of the reed contacts from the moment of action (short-circuiting) to the moment of reset (opening) of contacts at the first measurement and the current return , wherein the reed switch is returned to its original position, further, the current is increased to I₂>I₁, is measured ( is the magnitude of the current amplitude for the second measurement) and time from the moment of action to the reset at this measurement, then the current is increased to I₃>I₂, is measured ( is the magnitude of the current amplitude for the third measurement) and time from the moment of action to reset, then the current is increased to I₄>I₃ and so on, repeating previous operations before I_n>I_n-1, where , n-1 is number of necessary measurements of time and current and (i= 1, 2…n), N is current multiplicity in the IC with respect to the minimum current of the reed switch , n=30÷40, N=50÷100, then the dependence of the current amplitude in the conductor on the time of the closed state from the moment of operation of the first reed switch to its return is constructed, and the obtained dependence is entered in the microprocessor (in (1), where is the current amplitude in the conductor, C_SF is the current scale factor in IC at the current in the conductor, and h is the distance from the conductor to the contacts of the reed switch, ω_K is the number of turns in the first IC, l_k is the length of the first IC), then reed switch is at the design point close to the conductor and when it is triggered with microprocessor the time of closed state of the reed switch is measured, and according to (1) dependence the amplitude of the is determine, characterized in that at each i-m measurement and in the inductor is measured and also i-th actuating current of reed, after all the measurements a dependency (2) is built, the dependence (2) and are introduced in the microprocessor, then in the laboratory in the second IC the second normally open reed switch is put so that their longitudinal axes coincide, then the AC voltage U^(K2) is supplied, the angle ψ between the supplied voltage U^(K2) and current flowing in the second IC is determined, then gradually increasing U^(K2) to increase of current in IC to where is the smallest current flowing in IC, at which the actuation of the second reed switch (contact closure) occurs, is the current amplitude, the value of the time of closed state of contacts of the second reed switch from the time of action to reset (contact opening) and the reset current at which the reed switch returns to its original position are measured, then U^(K2) is increase to the increase of current in IC to is measured, where is the current amplitude, time from moment of action to reset, and the actuating current then U^(K2) is increased to the increase of the current in IC to is measured, where is the current amplitude, time from moment of action to reset, and the actuating current , then U^(K2) is increased to increase of current in IC to and so on, repeating the previous operations to , where is the current in IC when the voltage applied U^(K2)=120, k-1 is the number of required measuring of time and currents , and (i=1, 2…k), k=10÷15, further the dependence of the current amplitude and of the actuating current operation in IC from time of closed state from the moment of action of the reed switch to the moment of its reset is built, and the dependencies are entered, and ψ in the microprocessor, then the first reed switch is set in close proximity to the conductor, and the second IC with the second reed switch is connected to the terminals of the secondary winding of the voltage transformer, both of the reed switches can operate in parallel, therefore, the microprocessor can simultaneously perform the following operations, with the closure of the contacts of the first reed switch installed in close proximity to the conductor, astronomical time and is recorded, at short-circuiting and opening of its contacts occurred, respectively, then using a microprocessor the current in the conductor is found from the dependence (2) after , at which the reed switch has closed contacts, the time and is found from formulae and where and are the time intervals from the transition of the sinusoid through zero to triggering and from the moment of reset until the next transition through zero, respectively, then the astronomical time of transition of the current sinusoid through zero by the formula is determined, at the actuation of the second reed switch with a microprocessor astronomical time is recorded, the time of closed state of the reed switch is measured, upon opening the second reed switch contacts in IC with a microprocessor astronomical time is recorded and after dependencies (3) the current amplitude and of the actuating current values are determined, then the time and is found of formulae and where and are the time intervals from the transition of the sinusoid through zero to triggering and from the moment of reset until the next transition through zero, respectively, and the astronomical time of transition of the current sinusoid through zero in the second IC is determined by the formula then the transition of a voltage sinusoid through zero is defined by the formula this time is remembered until the determination of the next transition of voltage through zero, then using a microprocessor phase of steady-state AC current in the conductor is determined relative to the voltage according to the formula

EFFECT: expansion of the field of use due to the determination of the phase of the steady-state alternating current by fixing the astronomical time of action and reset moments of reed switches, determining the moments of transition of the current and the voltage sinusoid through zero used as the reference point.

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КПР - C_SF

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