JPH0260407A - Air cooler for current conductor - Google Patents

Abstract

PURPOSE:To prevent temperature rise even upon faults of an inverter by detecting the temperature of a current conductor through an optical fiber temperature detecting means and switching a power source circuit directly through a control means based on a detected signal. CONSTITUTION:An optical fiber thermometer 11 detects the temperature of a conductor 3a through a temperature sensor 10. If the detected temperature signal is not within an allowable range, a current relay 13 closes a contact 13a and actuates an electromagnetic contactor 15. Consequently, a contact 15b is opened to separate the output from an inverter 9 while a contact 15a is closed to operate a motor fan 4 directly through a commercial power source circuit. Consequently, the conductor 3a can be cooled even upon fault of the inverter 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a device for forced air cooling of a current conductor such as a phase-separated bus bar used in a power plant.

[Prior Art] Fig. 2 is a schematic configuration diagram showing a conventional air cooling device for current conductors, as disclosed in, for example, Japanese Utility Model Publication No. 60-1.1714. The case of cooling will be explained.

In Figure 2, 1 is the generator (G), 2 is the main transformer, 3
is a phase separation bus connecting these generators] and the main transformer 2, 3a is a conductor of this phase separation bus 3, and 4 is a conductor 3.
5 is an electric blower for blowing cooling air to the phase separation bus bar 3 through a ventilation duct 6 to create a circulating flow in order to cool the air; Both the electric blower 4 and the heat exchanger 5 are installed in a ventilation duct 6. Further, 7 is a current transformer (current detecting means) for detecting the value of the circuit current flowing through the conductor 3a, 8 is a transducer electrically connected to the current transformer 7, and 9 is a current transformer for detecting the value of the circuit current flowing through the conductor 3a. This is an inverter device (INV) installed in series in the power supply circuit of the electric blower 4 in order to receive a current detection signal from the current flow device 7 and control the operating state of the electric blower 4 based on the current detection signal.

Next, the operation will be explained. The magnitude of the main circuit current flowing from the generator 1 to the main transformer 2 through the conductor 3a is detected by the current transformer 7, and the detection signal is sent to the transducer 8.
The signal is input to the inverter device 9 via.

The inverter device 9 controls the power input to the electric blower 4 according to the current detection signal from the current transformer 7, and performs variable speed operation so that the electric blower 4 rotates in a predetermined speed pattern. A program is pre-installed, so that the cooling air volume corresponding to the current detection signal is automatically supplied to the phase separation bus 3, and the temperature of the conductor 3a is maintained in an appropriate state. In other words, this conventional device achieves energy-saving operation of the electric blower 4 by supplying necessary and sufficient cooling air according to the main circuit current value.

Note that Japanese Utility Model Publication No. 60-11714 gives an example of variable speed operation corresponding to on/off operations at the auxiliary contacts of a plurality of current relays installed in the secondary circuit of a current transformer. Unlike such sequence control, the conventional device shown in FIG. operation is realized.

[Problems to be Solved by the Invention] Conventional current conductor air cooling devices are configured as described above, and since the electric blower 4 sometimes requires delicate control for variable speed operation, the current transformer 7 If a failure occurs in the inverter control input system, such as the transducer 8 or the transducer 8, or if an internal abnormality occurs in the inverter device 9, there are problems in terms of reliability and economy due to energy saving. In other words, if the phase separation bus 3 is operated at a lower or lower air volume than the expected cooling air volume determined in response to a certain main circuit current due to such a failure, abnormal temperature of the conductor 3a, etc. There is a risk that excessive current flow loss may occur due to this, making variable speed operation impossible from the standpoint of reliability and control accuracy.On the other hand, if an unnecessarily large amount of air is blown, There is a risk that the drive energy of the electric blower 4 will be wasted.

This invention was made to solve the above-mentioned problems, and even if a failure occurs in the inverter control input system or inverter device, it prevents overheating of the current conductor and excessive current loss, and also prevents the electric blower from overheating. An object of the present invention is to obtain a highly reliable air cooling device for a current conductor that can prevent wasting of driving energy.

[Means for Solving the Problems] An air cooling device for a current conductor according to the present invention includes an optical fiber type temperature detection means for extracting and detecting the temperature of the current conductor using an optical fiber, and this optical fiber type temperature detection means. The control means is provided for disconnecting the electric blower from the inverter device and directly connecting the power supply circuit to the electric blower when the detection result from the electric blower exceeds a predetermined temperature tolerance range.

[Function] The current conductor air-cooling device of the present invention can prevent the temperature of the current conductor from rising abnormally due to a failure in the inverter control input system (current detection means, etc.) or the inverter device. Alternatively, even if the current conductor is excessively cooled using wasted energy, such a state can be detected when the detection result of the optical fiber type temperature detection means deviates from a predetermined temperature tolerance range. At this time, since an optical fiber type temperature detection means is used, even if a large current flows through the current conductor and a strong magnetic field is formed around its outer periphery, the temperature can be detected without being affected by induction disturbances caused by the magnetic field. I can do it. When an abnormality is detected by the optical fiber temperature detection means, the control means disconnects the electric blower from the inverter device, connects it directly to the power supply circuit, and switches from variable speed operation to commercial frequency operation.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
The figure is a schematic configuration diagram showing an air cooling device for a current conductor according to an embodiment of the present invention. In the figure, the same reference numerals as those described above indicate the same parts, and the explanation thereof will be omitted. Also in this embodiment, a case will be described in which a phase separation bus bar serving as a current conductor is cooled.

In FIG. 1, 10 is an optical fiber temperature sensor attached to the conductor 3a, and 11 is an optical fiber type humidity sensor connected to the temperature sensor 10 by an optical fiber 12 and installed outside the phase separation bus 3.

This thermometer 11 is placed at a ground potential position so as not to be affected by the magnetic field of the current flowing through the conductor 3a, and upon receiving an optical signal related to the temperature from the optical fiber 12, the thermometer 11 measures the current corresponding to the temperature of the conductor 3a. These temperature sensors 10. The temperature of the conductor 3a is measured using the thermometer 1] and the optical fiber 12.
An optical fiber type temperature detecting means is configured to take out and detect the temperature at the .

Further, 13 is a current relay electrically connected to the thermometer 11, and a temperature detection signal from the thermometer 11 is set in advance.
It operates when the temperature falls outside a predetermined allowable range, and drives the manual return type contact 13a from the open state to the closed state. 14 is a step-down transformer connected to the power supply circuit system 4a for the electric blower 4; 15 is an electromagnetic contactor connected to this transformer 14 via a contact 13a;
When the switch is in the closed state, it is excited and drives the contact 15a from the open state to the closed state, and also drives the contact 15b from the closed state to the open state, disconnecting the electric blower 4 from the inverter device 9 and disconnecting the power supply circuit system 4a from the electric blower. It connects directly to 4. In this way, current relay 13. Magnetic contactor 1
5 constitutes a control means.

Note that 16 is a no-fuse breaker interposed between the inverter device 9 and the power supply circuit system 4a.

Next, the operation of the apparatus of this embodiment will be explained.

Current transformer7. Transducer 8 and inverter device 9
is operating normally, a preset amount of cooling air is blown based on the main circuit current value detected by the current transformer 7, in exactly the same way as the conventional device, and the conductor of the phase separation bus 3 is The conductor 3a is appropriately cooled to achieve thermal equilibrium with the conduction loss of the conductor 3a and maintain the conductor temperature within a predetermined temperature tolerance range.

On the other hand, if a trouble occurs such as a failure in the inverter control input system such as the current transformer 7 or the lance duplexer 8, or some kind of internal abnormality in the inverter device 9,
If a situation arises in which only a smaller amount of cooling air can be blown to the conductor 3a than the expected air volume corresponding to the main circuit current value,
The conductor 3a is overheated due to current loss in the conductor 3a, but at this time, the optical fiber temperature sensor 10. Information about the abnormal temperature rise of the conductor 3a is finally transmitted to the current relay 13 by the optical fiber 12 and the optical fiber thermometer 11, and when the temperature falls outside the preset temperature tolerance range, the current relay 13 is activated. Then, the contact 13a is driven to close.

As a result, the electromagnetic contactor 15 is excited, and its contact 15
a and 15b are driven to close and open, respectively, and the electric blower 4
is separated from the inverter device 9 and directly connected to the power supply circuit system 4a, and is switched from variable speed operation to commercial frequency operation. Therefore, further abnormal heat generation of the conductor 3a is prevented, and the conductor temperature can be restored to within the temperature tolerance range. After this, no fuse breaker 1
6 is opened, the abnormality is checked, and when the draft is restored, the no-fuse breaker 16 is reclosed.
By manually returning the contact point 13a, normal variable speed operation of the electric blower 4 can be resumed.

Furthermore, if a similar failure or abnormality causes a cooling air volume that is considerably larger than the expected air volume corresponding to the main circuit current value to flow to the conductor 3a, and this conductor 3a is overcooled, the same procedure as described above can be applied. Optical fiber temperature sensor 10. When the optical fiber thermometer 11 detects that the conductor temperature is outside the permissible temperature range, the electric blower 4 is disconnected from the inverter device 9 and directly connected to the power supply circuit system 4a, changing from variable speed operation to commercial frequency operation. This makes it possible to check for abnormalities and carry out remedial work, as well as realize energy-saving operation of the electric blower 4.

Furthermore, in this embodiment, in order to detect the temperature of the conductor 3a, an optical fiber type temperature detection means is used and the temperature information of the conductor 3a is led to the ground potential position outside the phase separation bus 3. Even in the strong magnetic field formed by the large current in equipment that passes a large current through the conductor 3a, such as the separation bus 3, temperature sensors and optical fibers are completely immune to the effects of induction disturbances caused by the magnetic field. without receiving
Accurate temperature detection is possible. In addition, optical fiber] 2,
Although the conductor 3a to which a high voltage is applied is directly connected to an external ground potential, there is no risk of a ground fault due to the high insulation properties of the optical fiber 12 itself.

In the above embodiment, an example was shown in which the electric blower 4 is switched to commercial frequency operation even when the conductor 3a is overcooled due to a failure or abnormality in the inverter control human power system, etc. However, for the phase separation bus 3, Switching control may be performed targeting the most critical conductor heating level.

In addition, in 1-Record, the air cooling device for the phase separation bus 3 was explained, but the present invention is not limited to this, and can be similarly applied to any other conductive device that conducts current. Therefore, the same effect as the above embodiment is achieved. Further, in the above embodiment, a closed circulation type cooling air passage structure having a heat exchanger 5 may be used, or an open cooling air passage structure having no heat exchanger may be used. be effective.

[Effects of the Invention] As described above, according to the present invention, the temperature of the current conductor is detected by the optical fiber type temperature detection means, and based on this temperature information, the electric blower is controlled by the control means without going through an inverter device. Since the structure is configured to switch directly to the inverter, it not only saves energy during normal variable speed operation using the inverter, but also provides accurate temperature control even if a failure occurs in the inverter control system or the inverter. [Switching to commercial frequency operation etc. based on the information] 1), eliminating abnormal temperature conditions in the current conductor, and achieving extremely high reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an air cooling device for a current conductor according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing a conventional air cooling device for a current conductor. In the figure, 3a - conductor, 4 - electric blower, 4a -
・Power supply circuit system, 7-current transformer (current detection means), 9-inverter device, 10-optical fiber temperature sensor, 11-optical fiber thermometer, 12-optical fiber, 13-current relay, 13 a- Manual return type contact, 15-magnetic contactor, i
5a, 15b - contacts. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] an electric blower that blows cooling air to the current conductor to cool the current conductor; a current detection means that detects the value of the current flowing through the current conductor; and an operation of the electric blower based on the detection result from the current detection means. In an air cooling device for a current conductor, which includes an inverter device connected in series with a power supply circuit for the electric blower to control the state, the temperature of the current conductor is detected by extracting it through an optical fiber. an optical fiber type temperature detection means, and when the detection result from the optical fiber type temperature detection means is out of a predetermined temperature tolerance range, the electric blower is disconnected from the inverter device and the power supply circuit is directly connected to the electric blower. An air cooling device for a current conductor, characterized in that it is equipped with a control means for controlling a current conductor.