Pico Hydro Power
Generating Electricity
9 GENERATING ELECTRICITY
9.1 Safety Warning 9.2 Electrical Standards 9.3 Earth-fault protection 9.4 Generator Options 9.5 Using 3-Phase Induction Motors as Single-Phase Generators. 9.6 Electronic Load Control 9.7 Alternatives to load control 9.8 Selection and Sizing of Generator, Capacitors, Cable and Protection Equipment 9.9 Installation and Connection
9.2 Electrical Standards
National electrical standards should be followed. In some countries, special standards for micro hydro and/or isolated village electrification have been agreed. These standards should be followed even if they disagree with the recommendations given here. Please read the disclaimer at the front of this manual.
9.3 Earth-fault protection
An earth fault occurs, for example, if a live wire becomes loose inside a device and touches its metal case. An RCD (Residual Current Device) will disconnect the supply if a fault like this causes a large enough current to flow to the ground (i.e. if the case is earthed or someone touches the case and makes a path to earth). It can also disconnect the supply if someone accidentally touches a live wire causing current to be conducted through them to the ground. This reduces the risk of fatal electric shocks though these can still occur if someone touches both line and neutral and is insulated from the earth. The RCD required is one with a residual tripping current of 30mA. It should be connected directly to the generator as shown in Figure 9-7.
9.1 Safety Warning
Electricity can be extremely dangerous. If a person comes into contact with a live wire or faulty equipment with a voltage higher than 50V, it is possible for them to receive a fatal electric shock. The electricity generating system described here is designed to operate at mains voltage (120V or 220V AC depending on the national standards). Anyone carrying out electrical installation work at these voltages must be supervised by a qualified and experienced
9 GENERATING ELECTRICITY
9.1 Safety Warning 9.2 Electrical Standards 9.3 Earth-fault protection 9.4 Generator Options 9.5 Using 3-Phase Induction Motors as Single-Phase Generators. 9.6 Electronic Load Control 9.7 Alternatives to load control 9.8 Selection and Sizing of Generator, Capacitors, Cable and Protection Equipment 9.9 Installation and Connection
9.2 Electrical Standards
National electrical standards should be followed. In some countries, special standards for micro hydro and/or isolated village electrification have been agreed. These standards should be followed even if they disagree with the recommendations given here. Please read the disclaimer at the front of this manual.
9.3 Earth-fault protection
An earth fault occurs, for example, if a live wire becomes loose inside a device and touches its metal case. An RCD (Residual Current Device) will disconnect the supply if a fault like this causes a large enough current to flow to the ground (i.e. if the case is earthed or someone touches the case and makes a path to earth). It can also disconnect the supply if someone accidentally touches a live wire causing current to be conducted through them to the ground. This reduces the risk of fatal electric shocks though these can still occur if someone touches both line and neutral and is insulated from the earth. The RCD required is one with a residual tripping current of 30mA. It should be connected directly to the generator as shown in Figure 9-7.
9.1 Safety Warning
Electricity can be extremely dangerous. If a person comes into contact with a live wire or faulty equipment with a voltage higher than 50V, it is possible for them to receive a fatal electric shock. The electricity generating system described here is designed to operate at mains voltage (120V or 220V AC depending on the national standards). Anyone carrying out electrical installation work at these voltages must be supervised by a qualified and experienced