In Jordan's Code, the normal operation frequency is between 49.95 to 50.05 Hz and this limitation turns to be from 48.75 to 51.25 Hz when the system is operating under stress.
We consider four cases: normal operating conditions, change in the oscillator natural frequency (fault 1), increase in process noise variance by an order of magnitude (fault 2), and increase in measurement noise by an order of magnitude (fault 3).
Table 1 FCAS requirements in 8 situations Regulation Regulation raise Regulation lower Contingency Fast raise and fast lower (6 s response to arrest the frequency deviation) Slow raise and slow lower (60 s response to keep the frequency within the single contingency band) Delayed raise and delayed lower (5 min response to retune the frequency back to the normal operating band).
The Security and Quality of Supply Standard (SQSS) states that the system frequency of the GB network under normal operating conditions should be maintained at 50 Hz within operational limits of ±0.5 Hz [9].
Secondary frequency control, also called AGC or load frequency control (LFC), is implemented during emergency frequency events as well as under normal operating conditions [50, 64].
As expected, the frequency of membrane preservation operations and of repairs were higher than "normal" operating conditions.
Table 2 Parameters corresponding to normal operation and faulty conditions of oscillator (46) Fault 0, normal operating conditions Fault 1 Fault 2 Fault 3 θ 1 3.0 5.0 3.0 3.0 θ 2 10−1 10−1 1.0 10−1 θ 3 10−2 10−2 10−2 10−1 Parameter θ 1 is the oscillator natural frequency.
According AEMO standards, the frequency deviation must be brought back to its normal operating band within five minutes under any contingent event.
Tuning of these controllers is possible using a transfer function estimated from the frequency behaviour of a validated simulation model under normal operating conditions.
Fig. 6 Estimated fault number in the example 3, using Algorithm 2 as a function of time Table 3 Parameters corresponding to normal operation and faulty conditions of oscillator (46) in the example 3 Fault 0, normal operating conditions Fault 1 Fault 2 Fault 3 θ 1 3.0 5.0 3.0 1.0 θ 2 10−1 10−1 1.0 1.0 θ 3 10−2 10−2 10−2 10−1 Parameter θ 1 is the oscillator natural frequency.
