We report the results of photometry of the WZ Sge-type dwarf nova V455 And .
Observations were obtained over 19 nights in 2013 and 2014 .
The total duration of the observations was 96 h. We clearly detected three coherent oscillations with periods of 80.376 \pm 0.003 min , 40.5431 \pm 0.0004 min and 67.619685 \pm 0.000040 s. The 67.619685-s period can be the spin period of the white dwarf .
The 40.5431-minute period is the first harmonic of the orbital period .
The 80.376-minute oscillation can be a negative superhump because its period is 0.9 % less than the orbital period .
This oscillation was evident both in the data of 2013 and in the data of 2014 .
These results make V455 And a permanent superhump system which shows negative superhumps .
This is also the first detection of persistent negative superhumps in a WZ Sge-type dwarf nova .
In addition , the analysis of our data revealed incoherent oscillations with periods in the range 5–6 min , which were observed earlier and accounted for by non-radial pulsations of the white dwarf .
Moreover , we clearly detected an oscillation with a period of 67.28 \pm 0.03 s , which was of a low degree of coherence .
This oscillation conforms to the beat between the spin period of the white dwarf and the 3.5-h spectroscopic period , which was discovered earlier and accounted for by the free precession of the white dwarf .
Because the 67.28-s period is shorter than the spin period and because the free precession of the white dwarf is retrograde , we account for the 67.28-s oscillation by the free precession of the white dwarf .