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  2. Protective relay - Wikipedia

    en.wikipedia.org/wiki/Protective_relay

    An overcurrent relay is a type of protective relay which operates when the load current exceeds a pickup value. It is of two types: instantaneous over current (IOC) relay and definite time overcurrent (DTOC) relay. The ANSI device number is 50 for an IOC relay or a DTOC relay. In a typical application, the over current relay is connected to a ...

  3. Index of coincidence - Wikipedia

    en.wikipedia.org/wiki/Index_of_coincidence

    This count, either as a ratio of the total or normalized by dividing by the expected count for a random source model, is known as the index of coincidence, or IC or IOC [2] or IoC [3] for short. Because letters in a natural language are not distributed evenly , the IC is higher for such texts than it would be for uniformly random text strings.

  4. Inrush current - Wikipedia

    en.wikipedia.org/wiki/Inrush_current

    A discharged or partially charged capacitor appears as a short circuit to the source when the source voltage is higher than the potential of the capacitor. A fully discharged capacitor will take approximately 5 RC time periods to fully charge; during the charging period, instantaneous current can exceed steady-state current by a substantial ...

  5. Current limiting - Wikipedia

    en.wikipedia.org/wiki/Current_limiting

    An inrush current limiter is a device or devices combination used to limit inrush current. Passive resistive components such as resistors (with power dissipation drawback), or negative temperature coefficient (NTC) thermistors are simple options while the positive one (PTC) is used to limit max current afterward as the circuit has been operating (with cool-down time drawback on both).

  6. Short circuit ratio (electrical grid) - Wikipedia

    en.wikipedia.org/wiki/Short_circuit_ratio...

    Large penetration of the inverter-based resources (IBRs) reduces the short circuit level: a typical synchronous generator can deliver a significant overcurrent, 2-5 [7] p.u., for a relatively long time (minutes), while the component limitations of the IBRs result in overcurrent limits of less than 2 [7] p.u. (usually 1.1-1.2 p.u.). [4]

  7. Time constant - Wikipedia

    en.wikipedia.org/wiki/Time_constant

    An example response of system to sine wave forcing function. Time axis in units of the time constant τ. The response damps out to become a simple sine wave. Frequency response of system vs. frequency in units of the bandwidth f 3dB. The response is normalized to a zero frequency value of unity, and drops to 1/√2 at the bandwidth.

  8. Time-dependent viscosity - Wikipedia

    en.wikipedia.org/wiki/Time-dependent_viscosity

    In continuum mechanics, time-dependent viscosity is a property of fluids whose viscosity changes as a function of time. The most common type of this is thixotropy , in which the viscosity of fluids under continuous shear decreases with time; the opposite is rheopecty , in which viscosity increases with time.

  9. Proportional–integral–derivative controller - Wikipedia

    en.wikipedia.org/wiki/Proportional–integral...

    The dead time θ is the amount of time between when the step change occurred and when the output first changed. The time constant (τ p) is the amount of time it takes for the output to reach 63.2% of the new steady-state value after the step change. One downside to using this method is that it can take a while to reach a new steady-state value ...