99.—(1) Article 153 is amended as follows.
(2) In paragraph 1, for “each synchronous area” substitute “the GB synchronous area”.
(3) In paragraph 2—
(a)in the opening words before point (a), for “each synchronous area” substitute “the GB synchronous area”;
(b)in point (a), omit the words from “and, for the CE and Nordic synchronous areas” to the end of the sentence;
(c)for point (b) substitute—
“(b)the size of the reference incident shall be either—
(i)the largest imbalance that may result from an instantaneous change of active power such as that of a single power generating module, single demand facility, or single HVDC interconnector or from a tripping of an AC line; or
(ii)the maximum instantaneous loss of active power consumption due to the tripping of one or two connection points,
and the reference incident shall be determined separately for positive and negative direction;”;
(d)omit point (c);
(e)in point (d), for “the synchronous area” substitute “the GB synchronous area”.