JP2007014078A - Power system switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power system switching device which improves the reliability on output power. <P>SOLUTION: In a power system switching device where a normal power system 101 and an emergency power system 102 are connected to an output power system 105 via a power system switching device 104 and which is equipped with a control circuit 103 that controls the power system switching device 104 so that it may output power from the normal power system 101 to the output power system 105 at normality and that it may output power from the emergency power system 102 to the output power system 105 when it detects abnormality from an output current detector 106 that detects the abnormality of the power supply to the output power system 105, the control circuit 108 inhibits the switching to the emergency power system 102 when a voltage monitor 107 detects the abnormality of the emergency power system 102, and it does not perform the switching to the emergency power system 102 even if an output current detector 106 detects the abnormality of the power supply to the output power system 105. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power system switching device that is connected to a utility power system and an emergency power system, normally outputs power from the utility power system, and switches to the emergency power system when the output current exceeds a set value. This improves the reliability of output power.

  The conventional power system switching device supplies power to a plurality of loads in a large-capacity UPS, but when a load exceeding the capacity of the UPS is connected, the corresponding load is disconnected from the UPS and used as bypass system power. Some have a power system switching device for connection. The conventional power system switching device has been described as a power switching device that performs switching from the utility power system to the standby power system. However, "whether the output current exceeds the set value" is added to the system switching condition of this device. Some perform the following operations by combining with UPS and bypass power supply. When the above power system switching device is connected to a utility power system such as a UPS and an emergency power system such as a bypassed system power, normally the power from the utility power system is output and the output current exceeds the set value. Switch to the power system. Thereby, while suppressing the load of the said common power grid | system, the reliability of output electric power is ensured (for example, refer patent document 1).

JP-A-6-189470

  Although the conventional power system switching device can switch when the output current increases, there is a problem that even if the voltage of the emergency power system is abnormal, it switches to the emergency power system. In addition, when the control circuit fails, there is a problem that even if the output current increases, it cannot be switched to the emergency power system.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a power system switching device that improves the reliability of output power.

  In the present invention, the normal power system and the emergency power system are connected to the load unit via the switching means, and the abnormality in the supply of power to the load unit is performed so that the power is output from the normal power system to the load unit in normal times. An emergency system for monitoring an abnormality of an emergency power system in a power system switching device having a control means for controlling the switching means to output power from the emergency power system to a load unit when an abnormality is detected from the monitoring means to detect When the emergency monitoring means detects an abnormality in the emergency power system, the control means prohibits switching to the emergency power system, and even if the monitoring means detects an abnormality in the supply of power to the load unit The state in which power is output from the normal power system to the load unit without switching to the main power system is maintained.

  In the power system switching device according to the present invention, the normal power system and the emergency power system are connected to the load unit via switching means, and the power to the load unit is output so that the normal power system outputs power to the load unit in normal times. In an electric power system switching device having a control means for controlling the switching means so that power is output from the emergency power system to the load section when an abnormality is detected from the monitoring means for detecting an abnormality in supply of power, an abnormality in the emergency power system Emergency monitoring means for monitoring the system, and when the emergency monitoring means detects an abnormality in the emergency power system, the control means prohibits switching to the emergency power system, and the monitoring means detects an abnormality in the supply of power to the load section. Even if it is detected, the state where power is output from the utility power system to the load unit without switching to the emergency power system is maintained, so the power output is switched to the emergency power system when the emergency power system is abnormal. It is possible to prevent that the Waru.

Embodiment 1 FIG.
Embodiments of the present invention will be described below. 1 is a diagram showing a configuration of a power system switching apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a diagram for explaining a switching operation of the power system switching apparatus shown in FIG. In the figure, a normal power system 101 and an emergency power system 102 are connected to an output power system 105 as a load unit via a power system switch 104 as a switching means. An output current detector 106 as a monitoring means for detecting an abnormality in the power supplied to the output power system 105 is attached between the output power system 105 and the power system switch 104, and the detection result is controlled. It outputs to the control circuit 103 as a means. The control circuit 103 determines whether or not the output current exceeds the set value. If it exceeds, the control circuit 103 determines that the power system switch 104 is in an overload state and changes the status of the power system switch 104 from “normal power system 101 to output power system”. "Switch to connection to 105" to "Connect to connection from emergency power system 102 to output power system 105". The emergency power system 102 is provided with a voltage monitor 107 as emergency monitoring means, and the detection result is output to the control circuit 103. The control circuit 103 determines whether the voltage of the emergency power system 102 is normal or abnormal. If the voltage is abnormal, the control circuit 103 instructs the power system switch 104 to “connect from the emergency power system 102 to the output power system 105”. Switching is prohibited.

  In FIG. 2, the waveform of the normal system voltage is shown in FIG. 2A, the waveform of the emergency system voltage detected by the voltage monitor 107 is shown in FIG. 2B, and the waveform of the output voltage is shown. 2 (c), FIG. 2 (d) shows a signal in the output current state, and FIG. 2 (e) shows an operation signal of the power system switch 104, respectively. The state I is a steady load state and the emergency system voltage is normal. The state II is a steady load state and the emergency system voltage is low. The state III is an excessive state. The state where the emergency system voltage is small in the load state is shown.

  Next, the switching operation of the power system switching apparatus according to the first embodiment configured as described above will be described. First, as in the state I in FIG. 2, the output voltage is a normal value, the output current state is within the set value, and is a steady load state. The emergency system voltage detected by the voltage monitor 107 is within the set value, and the control circuit 103 determines that the emergency power system 102 is normal. In this case, the control circuit 103 continuously controls the power system switch 104 so that power is supplied from the normal power system 101 to the output power system 105. Next, as in the state II, the output voltage is a normal value and the output current state is a steady load state within the set value as in the state I, but the emergency system detected by the voltage monitor 107 The voltage is small, and the control circuit 103 detects that the emergency power system 102 is abnormal. In this case, the control circuit 103 prohibits the switching of the “switching from the emergency power system 102 to the output power system 105” of the power system switch 104.

  Next, as in the state of III, it is detected that the output voltage is an abnormal value and the output current state is an overload state exceeding the set value. As in the state II, the emergency system voltage detected by the voltage monitor 107 is small, and the control circuit 103 detects that the emergency power system 102 is abnormal. In this case, the control circuit 103 normally switches from the emergency power system 102 to the connection to the output power system 105. However, since this switching is prohibited here, the switching signal is not transmitted. Rather, the connection from the utility power system 101 to the output power system 105 is maintained. Thereby, even when the emergency system voltage of the emergency power system 102 becomes abnormal, the power output to the output power system 105 can be maintained. The emergency power system 102 immediately notifies the outside when an abnormality is detected, and performs maintenance of the emergency power system 102.

  According to the power system switching device of the first embodiment configured as described above, the emergency power system is provided with a voltage monitor, and switching to the emergency power system is prohibited when the emergency power system is abnormal. Therefore, the reliability of the output power can be ensured. In addition, although the example where the voltage of the emergency power system is decreased is shown here, when the voltage of the emergency power system becomes large or the frequency of the emergency power system becomes abnormal, Needless to say, the present invention can be similarly applied as long as it can be determined to be abnormal.

Embodiment 2. FIG.
3 is a diagram showing a configuration of a power system switching device according to Embodiment 2 of the present invention, and FIG. 4 is a diagram for explaining a switching operation of the power system switching device shown in FIG. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the control circuit 103, for example, a control circuit failure detection circuit 108 is provided as a control monitoring means for monitoring whether a control function such as a watchdog timer or a control voltage monitoring circuit is operating normally. When the operation is monitored and the control circuit failure detection circuit 108 recognizes “control function failure”, the control circuit 103 changes the status of the power system switch 104 to “connection from the normal power system 101 to the output power system 105”. To “connection from the emergency power system 102 to the output power system 105”.

  Next, the switching operation of the power system switching device according to Embodiment 2 configured as described above will be described. First, as in the state I in FIG. 4, the output voltage is a normal value, the output current state is within the set value, and is a steady load state. Then, there is no signal detected by the control circuit failure detection circuit 108, and it is determined that the control circuit 103 is normal. In this case, the control circuit 103 continuously controls the power system switch 104 so that power is supplied from the normal power system 101 to the output power system 105. Next, as in the state II, the output voltage is a normal value and the output current state is within the set value and is in a steady load state as in the state I, but the control circuit failure detection circuit 108 uses the control circuit 103. Is detected to be abnormal. In this case, the control circuit 103 switches the power system switch 104 from “connection from the normal power system 101 to the output power system 105” to “connection from the emergency power system 102 to the output power system 105”. The power supply to the output power system 105 is switched from the normal power system 101 to the emergency power system 102.

  Next, as in the state of III, it is detected that the output voltage is an abnormal value and the output current state is an overload state exceeding the set value. As in the state II, the control circuit failure detection circuit 108 detects that an abnormality of the control circuit 103 is detected. In this case, since the connection from the emergency power system 102 to the output power system 105 has already been switched, the problem of the control circuit 103 is dealt with, so that even if the control circuit 103 has failed, it remains in an overload state. The utility power system 101 can be protected without becoming “output overload”. Further, when the control circuit failure detection circuit 108 detects an abnormality in the control circuit 103, it immediately notifies the outside so that the maintenance of the control circuit 103 is performed.

  According to the power system switching device of the second embodiment configured as described above, when the failure of the control circuit is detected, the power system is switched to the emergency power system. And protect the utility power system.

  Although not particularly shown in the above embodiments, the first embodiment and the second embodiment can be combined and implemented. In that case, the effects of any of the embodiments described above can be achieved. Moreover, in each said embodiment, although the example of the alternating current power system was shown, it cannot be overemphasized that it is applicable similarly also in a direct current power system.

It is the figure which showed the structure of the electric power system switching apparatus in Embodiment 1 of this invention. It is a figure for demonstrating operation | movement of the electric power grid switching apparatus shown in FIG. It is the figure which showed the structure of the electric power system switching apparatus in Embodiment 2 of this invention. It is a figure for demonstrating operation | movement of the electric power grid switching apparatus shown in FIG.

Explanation of symbols

101 utility power system, 102 emergency power system, 103 control circuit,
104 power system switch, 105 output power system, 106 output current detector,
107 Voltage monitor, 108 Control circuit failure detection circuit.

Claims (2)

A normal power system and an emergency power system are connected to the load unit via a switching means, and an abnormality in the supply of power to the load unit is detected so that power is normally output from the normal power system to the load unit. In the power system switching device comprising control means for controlling the switching means so that power is output from the emergency power system to the load section when the abnormality is detected from the monitoring means, the abnormality of the emergency power system is detected. Emergency monitoring means for monitoring, and when the emergency monitoring means detects an abnormality in the emergency power system, the control means prohibits switching to the emergency power system, and the monitoring means supplies power to the load section. Even if a supply abnormality is detected, the state of outputting power from the utility power system to the load unit is maintained without switching to the emergency power system. Location. A normal power system and an emergency power system are connected to the load unit via a switching means, and an abnormality in the supply of power to the load unit is detected so that power is normally output from the normal power system to the load unit. In the power system switching device comprising control means for controlling the switching means so that power is output from the emergency power system to the load section when the abnormality is detected from the monitoring means, the abnormality of the control means is monitored Provided with a control monitoring means, and when the control monitoring means detects an abnormality of the control means, the control means switches the output of the power to the load unit from the normal power system to the emergency power system. A power system switching device characterized by instructing the switching means.

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