Pursuant to Article 116 of the Energy Law

 
OF
 
THE
 
GENERATION
 
UNIT
 
FROM
 
TRANSMISSION
 
GRID 
4.3.8.1. Disconnecting of the generator due to frequency deviation 
4.3.8.1.1. In accordance with the level of frequency deviation f, generation unit must be 
capable to stay interconnected on the transmission grid for various periods, as follows:
- for frequency interval 47.5 Hz ≤ f ≤ 48 Hz, generation unit stays connected for at 
least 30 minutes; 
- for frequency interval 48.5 Hz ≤ f ≤ 49 Hz, generation unit stays connected for at 
least 90 minutes; 
- for frequency interval 49.0 Hz ≤ f ≤ 51 Hz, generation unit stays connected 
permanently; 
- for frequency interval 51 Hz ≤ f ≤ 51.5 Hz, generation unit stays connected for at 
least 30 minutes. 
4.3.8.1.2. Reversible hydro-generation unit. i.e. pumping unit whose nominal power is above 
100 MW, must be capable of prompt turn off from the transmission grid in the pumping 
regime for frequency range 49 Hz - 49,8 Hz. 
4.3.8.1.3. Generation unit must be capable to remain interconnected to the transmission grid 
for the frequency change in the amount of up to ± 2 Hz/s. To change the frequency greater 
than ± 2 Hz/s is allowed outage generating units from the grid after 1.25 s.
4.3.8.2. Disconnecting of the generator due to voltage deviation 
4.3.8.2.1. In accordance with the level of voltage deviation at the connection point on the 
transmission grid U
m
, generation unit must be capable to remain interconnected to the 
transmission grid for various periods, as follows: 
a) for connection points at 400 kV:
- for frequency interval 90%U
nom
< U
m
≤ 95%U
nom
, at least 60 minutes; 
- for frequency interval 95%U
nom
< U
m
≤ 105%U
nom
, permanently; 
- for frequency interval 105%U
nom
< U
m
≤ 110%U
nom
, at least 60 minutes; 
b) for connection points at 110 kV and 220kV:
- for frequency interval 85%U
nom
< U
m
≤ 90%U
nom
, at least 60 minutes; 
- for frequency interval 90%U
nom
< U
m
≤ 110%U
nom
, permanently; 
- for frequency interval 110%U
nom
< U
m
≤ 115%U
nom
, at least 60 minutes. 
cosφ 
U
m
[%] 

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43 
4.3.8.2.2. In the quasi-stationary state, when the voltage at the connection point is outside the 
values specified in paragraph 4.3.8.2.1. generating units may be excluded from the grid by 
application of automatic device.