A excitation system and a generator arrangement with the excitation system is proposed. The excitation system comprises a converter adapted for converting an AC current to a DC current, a switching device for short circuiting an AC input of the converter, and an arc detection device for detecting an arc fault in the excitation system and for actuating the switching device upon detecting the arc fault. Therein, the switching device comprises an irreversible switch adapted for short circuiting the AC input such that the arc fault is quenched. This provide a comprehensive protection against arc faults.

Protection devices prevent damage to synchronous generators during loss-of-field events. In various embodiments, a first protective element is associated with a first protection zone to protect a generator from a loss-of-field event at full load. A second protective element is associated with a second protection zone to prevent thermal overload during underexcited operation of the generator and to protect from loss-of-filed at light load. A third protective element associated with a third protection zone limits operation of the generator within the generator's specific steady-state stability limits. A fourth protective element is associated with a fourth protection zone to provide an alarm prior to operation of the second protective element. In various embodiments, characteristics and limits of each of the protective elements are defined in the same plane (specifically, the P-Q plane) to simplify settings and allow for visualization of the element characteristics and the generator capability curve at one or more temperatures or cooling capacities.

A differential protection method for generating a fault signal includes measuring current measurements at least at two different measuring points of a multiphase transformer for each phase. The current measurements for each phase are used to form differential current values and stabilization values. The fault signal is generated if it is determined during a trigger region check that a measurement pair of at least one of the phases, being formed by using one of the differential current values and the associated stabilization value in each case, is in a predefined trigger region. In order to be able to selectively and reliably distinguish an external fault from an internal fault, the transformer has a grounded star point and a zero system current flowing through the star point is used to form the stabilization values. A corresponding differential protection device is provided for performing the differential protection method.

A device for coupling a control unit with a voltage supply. An electrical connection between the voltage supply and the electrical control unit may be opened/closed with a switching element. An electrical resistor, which allows for a limited current flow from the voltage supply to the electrical control unit even when the switching element is open, is parallel to the switching element. Thus, an electrical energy store, such as a capacitor or a similar device, which is to buffer the input voltage at the electrical control unit, is chargeable even when the switching element is open. This is to avoid adverse effects caused by the charging of a capacitor at the input of the control unit when the switching element is closed.

A method for enhancing an over-voltage protection by an over-voltage protection device for a generator is provided. The device includes a high voltage excitation off (HEO) circuit lowering an over-voltage level by an over-voltage lockout control value and a voltage-dependent Ki-Kp (VoKiKp) circuit 30 decreasing an over-voltage generation time by a voltage difference value of a battery voltage. A generator setting voltage is provided to operate the over-voltage and the voltage difference value of the generator 1. The over-voltage level is lowered and the over-voltage generation time is minimized, thereby enhancing the over-voltage protection of the regulator of the generator.

The method of control according to the invention slaves a DC voltage generated by the alternator to a predetermined setpoint value by controlling an excitation current flowing in an excitation circuit comprising an excitation winding of a rotor of the alternator. The excitation current is controlled by means of a semiconductor switch, in turn controlled by a control signal having a predetermined period. The method comprises a detection of a failure of the excitation circuit. At least one short-circuit of the excitation winding is detected. According to another characteristic of the method, the control signal is generated on the basis of a combination of a setpoint signal formed by pulses of the predetermined period exhibiting a duty ratio representative of the setpoint value and of a detection signal indicative of the short-circuit.

System (17) for managing a supply voltage (B+A) of an onboard electrical network of a motor vehicle comprises a device (2, 4, 9, 16) for regulating the supply voltage and a device (10, 11) for protecting the onboard electrical network against overvoltages, the two devices together controlling an excitation of an alternator supplying the onboard electrical network. According to the invention, the protection device is separate from the regulating device. An overvoltage signal (OVD) generated by the protection device (11) and controlling the excitation has priority over an excitation signal (EXC) generated by the regulating device. The regulating device and the protection device can be in the form of two separate electronic blocks on separate substrates.

Systems and methods are provided for controlling breaker operation of power systems during a close before excitation (CBE) operation. One method includes closing the breaker of a generator prior to alternator voltage excitation, using power sourced from a permanent magnetic generator (PMG) that is coupled to the alternator.

The present application discloses a flexible excitation system and a method for controlling the same. The flexible excitation system consists of a plurality of groups of flexible excitation power units connected in parallel, a deexcitation circuit unit and a flexible excitation control unit. The method for controlling the flexible excitation system includes: realizing the internal fault-tolerant operation control of the flexible excitation power units by cooperatively controlling AC circuit breakers and DC circuit breakers of the flexible excitation power units and a deexcitation switch; dynamically controlling ceiling voltage when terminal voltage drops by using the fast response control ability of the flexible excitation system, so as to improve the forced excitation output capacity of the self-shunt excitation system. Aiming at the possible overload problem of an excitation transformer during the operation of flexible excitation, an excitation transformer overload limiter for the flexible excitation system is provided to limit the operation state of the excitation transformer within an allowable overload operation range of equipment.

A excitation system and a generator arrangement with the excitation system is proposed. The excitation system comprises a converter adapted for converting an AC current to a DC current, a switching device for short circuiting an AC input of the converter, and an arc detection device for detecting an arc fault in the excitation system and for actuating the switching device upon detecting the arc fault. Therein, the switching device comprises an irreversible switch adapted for short circuiting the AC input such that the arc fault is quenched. This provide a comprehensive protection against arc faults.