Water turbine power generation system and control method for providing improved dynamic response to major power setpoint variations

A power generation system (1), characterised in that it comprises:

• a feeder link (6) comprising a connection interface (62) for connection to an AC grid (2);
• a turbine system (3) comprising an electrical machine (31) and configured to deliver a nominal electrical power Pnom to the feeder link (6);
• an energy storage system (14) connected to the feeder link (6);
• a control system (7) configured to control the operation of the power generation system (1), wherein the control system (7) is configured for:
• receiving from the AC grid (2) a first electrical power setpoint Ps0 to be delivered to the connection interface (62) and controlling the turbine system (3) to deliver an electrical power Pt0=Ps0 to the connection interface;
• and
• receiving another electrical power setpoint Ps1 from the AC grid (2), where variation in electrical power ΔPs=Ps1−Ps0 and |ΔPs|>Pnom*0.3;
• if Ps1>Ps0:
• a) applying a hydraulic setpoint to the turbine system (3) to increase its electrical power output Pti and prevent the energy storage system (14) from supplying electrical power to the connection interface (62);
• b) determining a power Pea that the energy storage system 14 can supply to the connection interface;
• c) when Pti+a power supported by electrical storage system Pea≥Ps1−a lower power deviation ε1, controlling the energy storage system (14) to deliver electrical power Pe1 to the connection interface to fulfil a requirement Ps1−the lower power deviation ε1≤Pe1+Pti≤Ps1+an upper power deviation ε2, with the lower power deviation ε1 and the upper power deviation ε2 tolerated by the AC grid (2) at the connection interface (62);
• or
• if Ps0>Ps1:
• n) applying the hydraulic setpoint to the turbine system in order to decrease its electrical power output Pti and prevent the energy storage system (14) from retrieving electrical power from the connection interface;
• o) determining the power Pea that the energy storage system (14) can retrieve from the connection interface (62);
• p) when Pti+Pea≤Ps1+ε2, controlling the energy storage system (14) to retrieve electrical power Pe1 from the connection interface with a view to fulfilling the requirement
• Ps1−ε1≤Pe1+Pti≤Ps1+ε2.

A method of controlling an electricity generation system (1) comprising:

• a feeder link (6) comprising a connection interface (62) for connection to an AC grid (2);
• a turbine system (3) comprising an electrical machine (31), a turbine (32) and a turbine controller (9), wherein the turbine controller is configured to deliver at least one fluid parameter setpoint to the turbine (32) influencing the electrical power delivered by the electrical machine (31), wherein the electrical machine (31) delivers an instantaneous electrical power Ph to the connection link (6);
• an energy storage system (14) connected to the feeder link (6);
• wherein the control method includes the following steps:
• a) receiving a first electrical power setpoint Ps0 to be delivered to the connection interface (62) and controlling the turbine system (3) so as to deliver an electrical power Ph=Ps0 to the connection interface;
• and
• b) receiving a subsequent electrical power setpoint Ps1 (2), where variation in electrical power ΔPs=Ps1−Ps0, where Ps1>Ps0;
• c) based on a predictive control model of the electrical power generated by the turbine system (3), determining successive operating parameters of the turbine controller (9) so that the Ph reaches Ps1 with a minimum amount of additional energy;
• d) until Ph=Ps1, applying electrical power Pb to the feeder link (6) by means of the energy storage system (14), where Pb+Ph=Ps1, and applying the successive operating parameters to the turbine controller (9).