Fuse

A fuse that protects against excessive current.

blockType: AcausalElectricPowerSystems.Switches.Fuse

Path in the library:

/Physical Modeling/Electrical/Switches & Breakers/Fuse

Description

Block Fuse it opens the circuit, protecting it from excessive current. The block provides the following modeling methods:

Opening time is independent of current — The fuse burns out when the current through it continuously exceeds the threshold value for a set period of time. This method assumes that the burnout time is independent of the current. It also implies that the heat in the fuse dissipates instantly as soon as the current drops below a certain threshold value.
Opening time depends on I^2*t — the fuse burnout depends on the energy dissipated in it. Nominal melting point value It is usually indicated in the technical specifications. If you choose this method, the fuse will blow out when

where
- — the time when the current exceeds the threshold current;
- — instantaneous current through the fuse;
- — the nominal value of the melting point from the technical documentation.
Use this method to operate in the high current range.
Opening time is tabulated — fuse burnout depends on the average tabular data of time versus current. These data indicate the time required for the fuse to burn out at a certain current, and are available in the technical specifications in the form of time versus current curves.

Select the appropriate curve and enter the appropriate current and time values as the parameter values. Tabulated currents and Tabulated opening times accordingly. Use this method for low currents.

Ports

Conserving

# + — positive port
electricity

Details

The electrical port connected to the positive terminal.

Program usage name

p

# − — negative port
electricity

Details

The electrical port connected to the negative terminal.

Program usage name

n

Output

# x — fuse status
scalar

Details

The output port associated with the fuse status. The port outputs the value 0 if the fuse is working properly, and 1 if the fuse is blown.

Dependencies

To use this port, check the box Signal output for fuse state.

Data types	`Float64`
Complex numbers support	No

Parameters

Main

# Tabulated currents — current data from time versus current curves
A | pA | nA | uA | mA | kA | MA

Details

The tabular current value from the time versus current curve specified in the technical description. Each element of this vector must be larger 0, and the vector must be strictly increasing.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time is tabulated.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`[1.9, 2.0, 2.5, 30.0] A`
Program usage name	`I_vector`
Evaluatable	Yes

# Time to fuse — the time it takes for the fuse to burn out
s | ns | us | ms | min | hr | d

Details

The time it takes for the fuse to burn out. If the current through the fuse continuously exceeds the threshold value during this time, the fuse switches to a high-resistance state and opens the circuit. If the current drops below the threshold value before the time expires, the fuse remains in a low-resistance state. If the current exceeds the threshold value again, the time counter restarts. When the default parameter value is 0. the fuse burns out immediately as soon as the current exceeds the minimum melting current. The parameter value must be greater than or equal to 0.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time is independent of current.

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`0.0 s`
Program usage name	`t_blow`
Evaluatable	Yes

# Rated current, I_rated — Rated operating current
A | pA | nA | uA | mA | kA | MA

Details

The rated current of the fuse from the technical documentation or the rated operating current.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time is independent of current or Opening time depends on I^2*t.

Units	`A` \| `pA` \| `nA` \| `uA` \| `mA` \| `kA` \| `MA`
Default value	`1.0 A`
Program usage name	`I_rated`
Evaluatable	Yes

# Signal output for fuse state — activating the output port for fuse status

Details

If the box is checked, the output port x is displayed on the block icon. The port outputs the value 0 if the fuse is working properly, and 1 if the fuse is blown.

Default value	`false (switched off)`
Program usage name	`enable_state_out`
Evaluatable	No

# Fuse resistance R — fuse resistance
Ohm | mOhm | kOhm | MOhm | GOhm

Details

The resistance of the fuse in the low-resistance state. The parameter value must be greater than 0.

Units	`Ohm` \| `mOhm` \| `kOhm` \| `MOhm` \| `GOhm`
Default value	`0.01 Ohm`
Program usage name	`R_closed`
Evaluatable	Yes

# Open-circuit conductance G — the conductivity of the fuse in an open circuit
S | nS | uS | mS | 1/Ohm

Details

The conductivity of the fuse in an open circuit in a high-resistance state when the fuse is blown. The parameter value must be greater than 0.

Units	`S` \| `nS` \| `uS` \| `mS` \| `1/Ohm`
Default value	`1.0e-8 1/Ohm`
Program usage name	`G_open`
Evaluatable	Yes

# Ratio of minimum melting current to rated current, I_melt/I_rated — threshold melting current

Details

The minimum melting current determines the fuse burnout threshold. If the current through the fuse does not exceed this threshold, the fuse remains in a low-resistance state. When the default parameter value is 1, the threshold current is the same as the rated current. In most cases, the value of this parameter should be higher. 1. You can also set its value to less than 1 for situations where the fuse may blow out at a current level below the rated value (for example, due to high temperature or due to repetitive pulses). The parameter value must be greater than 0.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time is independent of current or Opening time depends on I^2*t.

Default value	`1.0`
Program usage name	`melting_to_rated_ratio`
Evaluatable	Yes

# Tabulated opening times — time data from time versus current curves
s | ns | us | ms | min | hr | d

Details

The tabular time value from the time versus current curve specified in the technical description. Each element of this vector must be greater than or equal to 0, and the vector must be strictly decreasing. The vector must have the same size as the vector Tabulated currents.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time is tabulated.

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`[10000.0, 1.0, 0.3, 0.001] s`
Program usage name	`t_blow_vector`
Evaluatable	Yes

# Parameterization — dependence of burnout time on current
Opening time is independent of current | Opening time depends on I^2*t | Opening time is tabulated

Details

Choose the parameterization method:

Opening time is independent of current — the fuse burns out if the current flowing through it continuously exceeds the threshold value for longer than the set time.
Opening time depends on I^2*t — the fuse burnout depends on the energy dissipated in it. Use this method to operate in the high current range.
Opening time is tabulated — fuse burnout depends on the average tabular data of time versus current. Use this method for low currents.

Values	`Opening time is independent of current` \| `Opening time depends on I^2*t` \| `Opening time is tabulated`
Default value	`Opening time is independent of current`
Program usage name	`parameterization`
Evaluatable	No

# Nominal melting, I^2*t — the amount of dissipated energy required to burn out the fuse
A^2*s

Details

The amount of energy dissipated in the fuse required to burn it out. This is the nominal melting point, or specified in the technical description. The value must be greater than or equal to 0.

Dependencies

To use this parameter, set for the parameter Parameterization meaning Opening time depends on I^2*t.

Units	`A^2*s`
Default value	`1.0 A^2*s`
Program usage name	`melting_energy`
Evaluatable	Yes