Search

BR-102025013771-A2 - Rotary Stabilizer and Method for Operating a Rotary Stabilizer

BR102025013771A2BR 102025013771 A2BR102025013771 A2BR 102025013771A2BR-102025013771-A2

Abstract

A rotary stabilizer (100) is described. The rotary stabilizer (100) is electrically connectable to an electrical network (200) and includes a synchronous capacitor (102), an initiator/exciter (116), and a power converter (126). The synchronous capacitor (102) includes a stator assembly (104) with a stator winding that is electrically connectable to the electrical network (200) and a rotor assembly (108) with a rotor winding. The initiator/exciter (116) includes a stator assembly (118) with a stator winding and a rotor assembly (120) with a rotor winding. The rotor assemblies (108, 120) are mechanically connected by a rotor shaft (110). A power converter (122) of the initiator/exciter (116) is electrically connected to the rotor windings of the synchronous capacitor (100) and the initiator/exciter (116) and is mounted for rotation on the rotor shaft (100). The power converter (126) has first terminals (138a, 138b, 138c) electrically connectable to the mains (200) and second terminals (140a, 140b, 140c) electrically connected to the stator winding of the initiator/exciter (116).

Inventors

  • Hooshang MIRAHKI
  • Vipulkumar Patel
  • Jonathan FOBBESTER

Assignees

  • GE ENERGY POWER CONVERSION TECHNOLOGY LIMITED

Dates

Publication Date
20260310
Application Date
20250702
Priority Date
20240703

Claims (10)

  1. 1. ROTARY STABILIZER (100) electrically connectable to an electrical network (200), characterized by the rotary stabilizer (100) comprising: - a synchronous capacitor (102) comprising: a first stator assembly (104) with a first stator winding that is electrically connectable to the electrical network (200), and a first rotor assembly (108) with a first rotor winding; - an initiator/exciter (116) comprising: a second stator assembly (118) with a second stator winding, a second rotor assembly (120) with a second rotor winding, wherein the second rotor assembly (120) is mechanically connected to the first rotor assembly (108) by a rotor shaft (110), and a first power converter (122) having first terminals electrically connected to the first rotor winding and second terminals electrically connected to the second rotor winding, wherein the first converter of power (122) is mounted for rotation on rotor shaft (110); and a second power converter (126) having first terminals (138a, 138b, 138c) electrically connectable to the mains (200) and second terminals (140a, 140b, 140c) electrically connected to the second stator winding.
  2. 2. ROTARY STABILIZER (100), according to claim 1, characterized in that the first power converter (122) is a rectifier.
  3. 3. ROTARY STABILIZER (100), according to any one of claims 1 to 2, characterized in that the second power converter (126) comprises: a rectifier (128) having AC terminals (138a, 138b, 138c) electrically connectable to the mains (200) and DC terminals, and an inverter (134) having AC terminals (140a, 140b, 140c) electrically connected to the second stator winding and DC terminals electrically connected to the DC terminals of the rectifier by a DC link.
  4. 4. ROTARY STABILIZER (100), according to any one of claims 1 to 3, characterized by further comprising a controller (142) adapted to control the operation of the second power converter (126).
  5. 5. ROTARY STABILIZER (100), according to claim 4, characterized in that the controller (142) is adapted to control the operation of the second power converter (126) based on the voltage at the second terminals (140a, 140b, 140c) of the second power converter (126) and the mains voltage.
  6. 6. ROTARY STABILIZER (100), according to any one of claims 4 to 5, characterized in that the controller (142) is adapted to control the operation of the second power converter (126) during a starting sequence of the rotary stabilizer (100), wherein: the second power converter (126) is operated in a motorized mode to supply power from the mains (200) to the second stator assembly (118), such that the starter/exciter (116) is operated as a motor to rotate the first rotor assembly (104) of the synchronous capacitor (102) from a standstill to a predefined rotational speed that is higher than a nominal rotational speed of the synchronous capacitor (102); when the synchronous capacitor (102) reaches the predefined rotational speed, the second power converter (126) is stopped, and the second power converter (126) is subsequently restarted and operated at A voltage control mode for controlling the excitation of the first rotor winding.
  7. 7. METHOD FOR OPERATING A ROTARY STABILIZER (100), as defined in any one of claims 1 to 3, characterized by the method comprising: during a starting sequence of the rotary stabilizer (100): operating the second power converter (126) in a motorized mode to supply power from the mains (200) to the second stator assembly (118), such that the starter/exciter (116) is operated as a motor to rotate the first rotor assembly (108) of the synchronous capacitor (102) from the stop to a predefined rotational speed that is higher than a nominal rotational speed of the synchronous capacitor (102), when the synchronous capacitor (102) reaches the predefined rotational speed, stopping the second power converter (126), and synchronizing the synchronous capacitor (102) with the mains (200).
  8. 8. METHOD, according to claim 7, characterized by further comprising, during the starting sequence of the rotary stabilizer (100), restarting the stopped second power converter (126) and operating the second power converter (126) in a voltage control mode to control the excitation of the first rotor winding during the starting sequence.
  9. 9. METHOD, according to claim 8, characterized by further comprising, during the starting sequence of the rotary stabilizer (100), operating the second power converter (126) restarted in voltage control mode while synchronizing the synchronous capacitor (102) with the electrical network (200).
  10. 10. METHOD, according to any one of claims 7 to 9, characterized by further comprising operating the second power converter (126) in a voltage control mode to control the excitation of the first rotor winding during normal operation of the rotary stabilizer (100).

Description

DESCRIPTION TECHNICAL FIELD [001] The present invention relates to rotary stabilizers and, in particular, to rotary stabilizers that include a synchronous capacitor (or synchronous compensator) that is electrically connected to an electrical system or network. BACKGROUND OF THE INVENTION [002] The use of a synchronous capacitor is known to support an electrical network with short-circuit power capacity and reactive power to mitigate voltage fluctuations and minimize disturbances during network fault conditions, for example. A synchronous capacitor is an unloaded synchronous rotating machine that is synchronized with the electrical network. In other words, unlike a conventional synchronous rotating machine, a synchronous capacitor is operated without any mechanical load connected to its rotor assembly, so there is no conversion of mechanical energy into electrical energy or vice versa. A synchronous capacitor can help stabilize the electrical network by generating or absorbing reactive power for network voltage regulation and providing rotational inertia to stabilize the network frequency. [003] A typical synchronous capacitor includes a stator assembly with a stator winding electrically connected to the mains or grid, optionally via a transformer. A synchronous capacitor also includes a rotor assembly with a rotor winding. The mains power is typically a three-phase mains power supply providing a three-phase alternating current (AC) supply to the stator winding, which generates a rotating magnetic field within the machine. Simultaneously, the rotor winding of the rotor assembly is typically excited by a direct current (DC). When operating under no-load conditions and in underexcited mode, a synchronous capacitor will absorb reactive power from the mains power. This is useful when there is an excess of reactive power in the system. When operating in overexcited mode, a synchronous capacitor will supply reactive power to the mains power. This can aid in voltage control and power factor correction. A synchronous capacitor can therefore behave at its stator terminals as if it were a three-phase inductor or capacitor, alternating between them according to the rotor excitation. Virtually no active power is transferred between a synchronous capacitor and the electrical network. [004] A synchronous capacitor can contribute to the overall stability of the power grid by providing dynamic support, for example, by helping to dampen oscillations and maintain stable operation of the main grid during faults or other disturbances. [005] A typical rotary stabilizer (1) is shown in Figure 1 and includes a synchronous capacitor (2), an exciter (4) and an auxiliary motor (6) (sometimes called a “pony motor”). The rotor assembly of the synchronous capacitor (2) includes a rotor shaft (8) which is supported at a driven end by a first bearing (10) and at a non-driven end by a second bearing (12). The synchronous capacitor (2) and the bearings (10, 12) are mounted on a base plate (14). The exciter (4) is normally located at the non-driven end and at least part of the exciter may be formed as part of the rotor shaft (8) – that is, at least part of the exciter may rotate with the rotor shaft. The stationary part of the exciter (4) can also be mounted on the base plate (14), as shown in Figure 1. The exciter (4) controls the intensity of the magnetic field in the rotor assembly, for example, by controlling the direct current supplied to the rotor winding, to regulate the reactive power of the synchronous capacitor (2). [006] The auxiliary motor (6) is typically located at the driven end of the rotor shaft (8). The auxiliary motor (6) is located on a separate base plate (16) (or concrete foundation), but may also be mounted on the same base plate (14) as the synchronous condenser. The auxiliary motor (6) may have any suitable construction and includes a rotor shaft (18). During a rotary stabilizer (1) start-up sequence, the auxiliary motor (6) is driven to rotate the rotor assembly of the synchronous condenser (2) to a rated rotational speed. The rotor shaft (18) of the auxiliary motor (6) is therefore coupled to the driven end of the rotor shaft (8) of the synchronous condenser (2), for example, by means of a suitable mechanical coupling (20) or a clutch mechanism. When the synchronous capacitor (2) reaches its rated rotational speed, it can be decoupled from the auxiliary motor (8) (or the auxiliary motor (8) can be operated in a de-energized mode) so that the synchronous capacitor (2) operates without load and is synchronized with the electrical network. Depending on the physical size of the synchronous capacitor (2) and the auxiliary motor (6), the total area of the rotary stabilizer (1) (i.e., including the base plates (14 and 16)) can be very large. For example, the length of the area can exceed 11 meters in some cases. [007] There is a need for an improved rotary stabilizer, with a smaller area and a simpler overall construction