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KR-20260062273-A - Device and method for uninterruptible power supply

KR20260062273AKR 20260062273 AKR20260062273 AKR 20260062273AKR-20260062273-A

Abstract

The present invention relates to an uninterruptible power switching device and method, comprising a commercial power circuit breaker that controls the supply of commercial power to a load, an emergency power circuit breaker that controls the supply of emergency power to the load, an emergency generator that generates the emergency power, and a controller that controls the commercial power circuit breaker and the emergency power circuit breaker to control the load burden ratio of the power before switching to the power after switching. The controller controls both the commercial power circuit breaker and the emergency power circuit breaker to a closed state so that parallel supply of the power before switching and the power after switching occurs during a stabilization time, and controls the output of the emergency generator to increase the load burden ratio of the power after switching to a set ratio, and then, when the stabilization time has elapsed, opens the commercial power circuit breaker or the emergency power circuit breaker so that the load burden ratio of the power after switching becomes 100%.

Inventors

  • 송찬호
  • 정영우

Assignees

  • 엘에스일렉트릭(주)

Dates

Publication Date
20260507
Application Date
20241029

Claims (8)

  1. Commercial power circuit breaker that controls the supply of commercial power to the load; An emergency power circuit breaker that controls the supply of emergency power to the above load; An emergency generator that generates the above emergency power; and A controller that controls the commercial power breaker and the emergency power breaker to control the load burden ratio of the power before switching to the power after switching, comprising: An uninterruptible power switching device characterized by the above controller controlling both the commercial power circuit breaker and the emergency power circuit breaker to a closed state so that parallel supply of the power before switching and the power after switching is achieved during a stabilization time, controlling the output of the emergency generator to increase the load burden ratio of the power after switching to a set ratio, and then opening the commercial power circuit breaker or the emergency power circuit breaker so that the load burden ratio of the power after switching becomes 100% after the stabilization time has elapsed.
  2. In paragraph 1, The above stabilization time is, An uninterruptible switching device characterized by a duration of 1 second to 30 seconds.
  3. In paragraph 1, The above stabilization time is, An uninterruptible power switching device characterized by a time during which the load burden ratio of the power after switching becomes 80 to 90% due to an increase or decrease in the output of the emergency generator in a parallel supply state of the power before switching and the power after switching.
  4. In paragraph 1, An uninterruptible switching device characterized by a load burden ratio setting ratio of 80 to 90%.
  5. A method of switching the power source before switching, which is commercial power or emergency power, to the power source after switching, which is emergency power or commercial power, A step of controlling both the commercial power breaker and the emergency power breaker to a closed state in the controller to supply the power before and after the switchover in parallel; A step of increasing or decreasing the output of the emergency generator while maintaining a parallel supply state during the stabilization time in the above controller, so that the load burden ratio of the power supply after the switching becomes a set ratio; and An uninterruptible switching method comprising the step of opening a commercial power breaker or an emergency power breaker when a stabilization time has elapsed in the controller, thereby switching so that the load burden ratio of the power after switching becomes 100%.
  6. In paragraph 5, The above stabilization time is, An uninterruptible switching method characterized by being 1 second to 30 seconds.
  7. In paragraph 5, The above stabilization time is, An uninterruptible power switching method characterized by a time during which the load burden ratio of the power after switching becomes 80 to 90% due to an increase or decrease in the output of the emergency generator in a parallel supply state of the power before switching and the power after switching.
  8. In paragraph 5, An uninterruptible switching method characterized by a load burden ratio setting ratio of 80 to 90%.

Description

Device and method for uninterruptible power supply The present invention relates to an uninterruptible switching device and method, and more specifically, to an uninterruptible switching device and method capable of preventing transient phenomena occurring during uninterruptible switching between a commercial power source and an emergency power source. Generally, various industrial facilities or equipment operate emergency generators to prepare for power outages. For example, an IDC (Internet Data Center) is a critical load facility in the event of a power outage, and it maintains multiple emergency generator facilities to prevent such outages. In particular, for uninterrupted power switching, it includes a soft load transfer switch and a CTTS (Closed Transition Transfer Switch), and implements a system that switches to the emergency power within 100ms when the commercial power is cut off. Figure 1 illustrates an example of a conventional uninterruptible switching device. Referring to FIG. 1, conventionally, a controller (100), a commercial power circuit breaker (200), and an emergency power circuit breaker (300) are included to selectively supply the commercial power (400) and the emergency power of the emergency generator (500) to the load (600). As a specific explanation of the operation, the process of switching to an emergency power source while the commercial power source (400) is supplied to the load (600) is explained. First, the controller (100) detects the need to switch from the commercial power supply (400) to the emergency power supply. That is, when the voltage of the commercial power supply (400) becomes below a predetermined set value or when a switching signal from the outside is input, a switching to the emergency power supply is decided. Next, the controller (100) starts the emergency generator (500) that generates emergency power to switch to the emergency power, and performs a ramp-up operation to increase the rotational speed of the emergency generator by increasing the fuel input to the emergency generator (500). The controller (100) checks the synchronization status of the commercial power supply (400) and the emergency power supply. At this time, synchronization refers to synchronization of phase, voltage magnitude, and frequency. The controller (100) checks the synchronization status of the commercial power supply (400) and the emergency power supply, and when the synchronization status is confirmed, the emergency power circuit breaker (300) is closed to supply the commercial power supply (400) and the emergency power supply to the load (600), thereby creating a parallel operation state. Figures 2 to 4 are graphs for explaining conventional uninterrupted operation control in terms of frequency. FIG. 2 is an ideal initial state, and FIG. 3 is a graph of the ramp-up and parallel operation states. The load (600) is assumed to have a capacity of 100 kW. As shown in FIG. 2, the emergency generator (500) is in an idle state, and the commercial power supply (400) is 100% borne by the power supply to the load (600). When a ramp-up operation is performed in this state, as shown in Fig. 3, the rotational speed of the emergency generator (500) increases, and the frequency of the generated power (voltage) also increases. In this state, when the previously described emergency power circuit breaker (300) is switched on, the commercial power (400) and the emergency power are supplied to the load (600) at a specific arbitrary ratio. The controller (100) opens the commercial power breaker (200) in a short time of less than 100ms in a parallel operation state. Accordingly, as shown in FIG. 4, the load ratio of the commercial power supply (400) becomes 0%, and the load burden ratio of the emergency power supply becomes 100%. At this time, the rapid load burden ratio changes, and therefore the frequency of the power supplied to the load (600) may be a frequency other than exactly 60Hz. Therefore, due to differences in frequency, a frequency response failure may occur where stable power supply is not achieved for a certain period. These problems may appear more severe when the power generation capacity of the emergency generator (500), which is an emergency power source, is small compared to the capacity of the load. The process of switching from the emergency power source to the commercial power source involves closing the commercial power circuit breaker (200) after synchronization is confirmed, and then opening the emergency power circuit breaker (300) within 100ms. In this case, the frequency of the commercial power supply is ideally fixed at 60Hz, so the above problem may not occur. However, in actual operation, the frequency of the commercial power supply may also fluctuate depending on the size of the load. Figure 5 is a graph showing the degradation of conventional frequency response. Referring to Fig. 5, the problems of the prior art described above can be analyzed using the swing equation. Th