  In this work, we explore two mechanisms that explain non-Gaussian behaviour
of power-grid frequency recordings in the South African grid. We make use of a
Fokker-Planck approach to power-grid frequency that yields a direct relation
between common model parameters such as inertia, damping, and noise amplitude
and non-parametric estimations of the same directly from power-grid frequency
recordings. We propose two explanations for the non-Gaussian leptokurtic
distributions in South Africa: The first based on multiplicative noise in
power-grid frequency recordings, which we observe in South Africa; The second
based on the well-known scheduled and unscheduled load shedding and rolling
blackouts that beset South Africa. For the first we derive an analytic
expression of the effects of multiplicative noise that permits the estimation
of all statistical moments - and discuss drawbacks in comparison with the data;
For the second we employ a simple numerical analysis with a modular power grid
of South Africa. Both options help understand the statistics of power-grid
frequency in South Africa - particularly the presence of heavy tails.
