Device for emulating a bimetallic strip, and device for protecting an electrical line from over-currents
AssigneeThales
InventorFrancis Abdesselam
Life of this patent
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Abstract
An emulating device for emulating a bimetallic strip, the emulating device comprising a current sensor capable of measuring a line current (IP) flowing through the emulating device, the emulating device being capable of providing a value representative of a cumulative thermal state over time t, which value is referred to as cumulative thermal state, by recursively adding a value representative of an initial thermal state, which value is referred to as initial thermal state, and a value representative of a present thermal state, which value is referred to as present thermal state, which is determined on the basis of the line current (IP).
Claims11
An emulating device (EMU) for emulating a bimetallic strip, the emulating device (EMU) comprising a current sensor (CC) capable of measuring a line current (IP) flowing through the emulating device (EMU), the emulating device (EMU) being capable of providing a value representative of a cumulative thermal state (Eth_n) over time t, which value is referred to as cumulative thermal state (Eth_n), by recursively adding a value representative of an initial thermal state (Eth_i), which value is referred to as initial thermal state (Eth_i), and a value representative of a present thermal state (Eth_on, Eth_off), which value is referred to as present thermal state (Eth_on, Eth_off), which is determined on the basis of the line current (IP) said emulating device (EMU) comprising a squaring operator (CAR) configured to square a value representative of the line current (IP), which value is output by the current sensor (CC), the value representative of the line current (IP) being an image voltage (Vinc) corresponding to the line current (IP), the emulating device (EMU) comprising at least one series RC circuit (CIRC_RC), and comprising at least one capacitor (Cm), at the terminals of which the cumulative thermal state (Eth_n) is measured, the series RC circuit (CIRC_RC) being connected to the squaring operator (CAR), the initial thermal state (Eth_i) being determined by the initial state of charge of the capacitor (Cm) at the end of a charging or discharging cycle, the present thermal state (Eth_on, Eth_off) being determined by the evolution of the state of charge of the capacitor (Cm).
An emulating device (EMU) for emulating a bimetallic strip, the emulating device (EMU) comprising a current sensor (CC) capable of measuring a line current (IP) flowing through the emulating device (EMU), the emulating device (EMU) being capable of providing a value representative of a cumulative thermal state (Eth_n) over time t, which value is referred to as cumulative thermal state (Eth_n), by recursively adding a value representative of an initial thermal state (Eth_i), which value is referred to as initial thermal state (Eth_i), and a value representative of a present thermal state (Eth_on, Eth_off), which value is referred to as present thermal state (Eth_on, Eth_off), which is determined on the basis of the line current (IP), said emulating device (EMU) comprising a squaring operator (CAR) configured to square a value representative of the line current (IP), which value is output by the current sensor (CC), said emulating device (EMU) comprising a programmable digital component configured to calculate the present thermal state (Eth_on, Eth_off) by means of the relationship:
- E
- th_on
- =
- I
- P
- 2
- I
- th
- 2
- ×
- (
- 1
- -
- e
- -
- t
- τ
- )
- where Eth_on is the value of the present thermal state when the emulating device (EMU) is supplied with the line current (IP), where IP is the value representative of the line current (IP), τ is a time constant and Ith is a conventional thermal current of the emulated bimetallic strip,
- and by means of the relationship:
- E
- th_off
- =
- I
- P
- 2
- I
- th
- 2
- ×
- e
- -
- t
- τ
- where Eth_off is the value of the present thermal state when the emulating device (EMU) is not supplied with the line current (IP),
- where IP is the value representative of the line current (IP) at the instant at which the emulating device (EMU) is no longer supplied with current, τ is a time constant and Ith is a conventional thermal current of the emulated bimetallic strip.
Dependencies are inferred from the claim text.