To an insufficiently damped electrical resonance inside the sub-synchronous frewas triggered energy into jecting reactiveby the occasion.the grid thereby restoring the voltage back to nominal. Howquency range, which was triggered by the occasion. ever, From16:52:33:490few 16:52:33:728, the sub-synchronous oscillation on the program lasted inside the 16:52:33:490 to power system From following to hundred milliseconds, because the wind farm’s active with the decreased about 238 ms and passed 16:52:33:728, the sub-synchronous within the of a Chlorisondamine diiodide nAChR single oscillation by way of about two power balance oscillation farm changed, cycles. The duration wind to cope together with the voltage dip as well as the reactive two cycles. The duration of a single oscillasted about 238 ms and passed via about cycle was about 119 ms the majority in the windand the oscillation frequency was about 8.4 Hz. Hz. lation cycle was about 119turbines thethe wind farm were disconnected by automatic proms and in oscillation frequency was about 8.4 tection systems. The de-load was triggered by an unexpected wind farm control method re2.three. Causes in the Accident sponse, as a result of an insufficiently damped electrical resonance in the sub-synchronous freFor the sub-synchronous oscillation occasion caused by lightning strike, Hornsea wind quency variety, which was triggered by the occasion. farm operator Orsted pointed out that the cause is insufficient damping in the subFrom 16:52:33:490 to 16:52:33:728, the sub-synchronous oscillation with the program synchronous oscillation frequency range. Soon after getting struck by lightning, the equivalent lasted about 238 ms and passed via about two cycles. The duration of a single oscilgrid strength at the grid-connected point is weak, which causes the oscillation from the lation cycle was about 119 ms and also the oscillation frequency was about eight.four Hz.16:52:34:Energies 2021, 14,5 ofreactive energy control program. As a result, the wind power gathering station voltage drops sharply, resulting in all wind turbine generators on Hornsea 1B and Hornsea 1C lowering to 0 MW as a result of overcurrent protection within the generators [2,8]. The accident was fundamentally caused by two causes. Around the one hand, the Hornsea offshore wind farm is connected for the UK most important power grid by way of a long distance submarine cable of 120 km. With all the boost of your length of high-voltage AC submarine cable, the equivalent grid strength of your grid-connected point from the offshore wind farm weakens, so the assistance effect of your AC grid on the voltage in the grid-connected point of your Hornsea wind farm decreases. On the other hand, Hornsea wind farm is actually a long-distance offshore wind power technique. So as to compensate the capacitive existing with the cable and limit the energy frequency overvoltage, Hornsea wind farm utilizes reactive compensation devices, including static var compensator (SVC), to enhance the transmission capacity of lines and enhance the transient stability on the method. Even so, resulting from its Ro60-0175 Technical Information unreasonable handle mode, the response of SVC has hysteresis, the peaks and valleys on the reactive power output curve are almost coincident with the over-surge and drop points of your bus voltage, plus the regulation of reactive energy is in the similar path because the voltage change. Beneath the combined action of those two variables, sub-synchronous oscillation occurred in Hornsea wind power technique. 3. Solutions When the Hornsea wind energy method suffered from asymmetric faults, which triggered sub-synchronous oscillation, there had been a lot of as.