Circuit Breaker TRV Recovery Calculator

Substation fault interruption & switchgear: Calculate Transient Recovery Voltage (TRV) peak (u_c), time to peak (t₃), Rate of Rise (RRRV), and IEC 62271 envelope compliance.

Short-Circuit Fault & System Specs

Rated Voltage U_r (kV RMS): Switchgear rated line-to-line voltage

Symmetrical Fault Current I_sc (kA): Breaking current at current zero

First-Pole-to-Clear Factor k_pp:

Amplitude Factor k_af: Standard IEC 62271-100 value = 1.4

Power Frequency f (Hz):

Fault Duty Condition:

Substation Stray Capacitance C_s (nF): Bushing + transformer capacitance

TRV Waveform & Rate of Rise (RRRV)

Peak Recovery Voltage (u_c)

Crest TRV amplitude

Rate of Rise (RRRV)

u_c / t₃ in kV / µs

Time to Crest (t₃)

Microseconds to peak voltage

Power Frequency Recovery (u_pf)

k_pp · U_r · √2 / √3

Natural Oscillation Frequency

f_n = 1 / (2 · π · √LC)

Thermal Re-ignition Risk

Arc zone dielectric recovery

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Frequently Asked Questions

What is Transient Recovery Voltage (TRV) in high-voltage circuit breakers?

When an SF₆ or vacuum circuit breaker extinguishes an alternating fault current at current zero, the system voltage immediately attempts to return to normal power frequency. The transient voltage oscillation across the opening breaker contacts during this initial post-arc microsecond window is called the Transient Recovery Voltage (TRV).

Why is the Rate of Rise of Recovery Voltage (RRRV) so critical?

Immediately after current zero, the arc column between contacts consists of a hot, decaying ionized plasma gas channel. If the electrical voltage across the contacts rises faster than the gas can cool and deionize (high RRRV, in kV/µs), dielectric breakdown occurs and current re-establishes, causing a thermal re-ignition failure.

What is the First-Pole-to-Clear factor (k_pp)?

In a three-phase system, when the first phase clears at its current zero, the neutral point of the remaining two faulted phases shifts in potential. This ungrounded neutral shift subjects the first-clearing breaker pole to an elevated recovery voltage, scaling the power-frequency voltage by k_pp = 1.3 to 1.5.