JP2005354754A - Dc power supply facility of power generation plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC power supply facility of a power generation plant for always supplying a constant voltage to a DC controlled load. <P>SOLUTION: The DC power supply facility of the power generation plant comprises a charger for supplying power to a DC station auxiliary machine in a power station of the power generation plant, a storage means and DC buses. The first DC bus is used for a load with a large transient capacitance. The second DC bus is used for a load with a transient capacitance smaller than the load. A voltage decrease due to a discharge from the storage means to the second DC bus through a DC voltage adjusting apparatus having a voltage boosting apparatus and a diode, is compensated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a DC power supply facility for a power plant.

  FIG. 6 shows an outline of a conventional DC power supply facility for a nuclear power plant. The DC power supply equipment is a direct current that supplies power to an emergency low-voltage bus 1, a DC power supply power receiving breaker 2, a charger 3 connected thereto, and a DC load that requires a DC power supply on the output side of the charger 3. It consists of a bus 6 and a storage battery 4 that is connected to the output side of the charger 3 via a storage battery circuit breaker 5 and that instantaneously supplies power when the input side of the charger 3 is stopped. The storage battery 4 is normally float-charged and becomes a DC power supply source when the entire plant AC power supply is lost as described above.

  The DC power supply equipment is installed as a power supply to a DC control load for operation control including emergency of the plant, and as an emergency power source when the AC power supply is lost. Actually, during normal plant operation, power is supplied from the DC power supply equipment to the operation of the circuit breaker and instrumentation control equipment, etc. When all plant AC power supply is lost, in addition to the load, the DC power supply equipment In the case of direct current loads for property protection systems and nuclear power plants, power is supplied to cooling equipment for reactor isolation. The load of property protection system includes emergency oil pumps, etc. These loads are installed for the purpose of property protection of the above equipment by supplying oil to bearings such as generators and turbines when AC power is lost Has been. In addition, the reactor isolation cooling system supplies coolant water to the reactor pressure vessel to prevent overheating of the fuel so that sufficient reactor water level can be achieved even if the reactor is isolated. It is installed for the purpose of doing. The steam generated by the decay heat of the reactor is used as the drive source, and the valve that controls the steam is driven by the DC power supply, so that cooling water can be injected into the reactor even when the AC power supply is lost. .

  The operation of the DC power supply equipment will be described below. During normal plant operation, the charger 3 connected to the emergency low-voltage bus 1 converts an AC power source into a DC power source, constantly charges the storage battery 4 serving as a power storage means, and normally operates the plant via the DC bus 6. Supplies power to DC loads such as control equipment that sometimes require DC power.

  When the AC power is lost, the input power of the charger 3 is lost, so the output of the charger 3 is also lost. As a result, electric power is supplied from the storage battery 4 without an instantaneous power failure, and direct current is supplied to a DC control load, an emergency oil pump that requires a DC power supply when the AC power supply is lost, and a reactor isolation cooling facility in a nuclear power plant. Supply power.

  FIG. 7 shows a graph of the discharge pattern of the storage battery 4 in the nuclear power plant. In the nuclear power plant, a large discharge capacity is released in a short time from the start of the discharge of the storage battery 4, and then a small discharge capacity is released over a long time. This is because power is supplied to the circuit breaker, the electric motor, etc. at the beginning of discharge, and the DC control load is supplied with a small capacity for a long time. FIG. 8 shows a graph of voltage fluctuation of the storage battery 4 when the storage battery is discharged with the above discharge pattern. The voltage of the storage battery 4 gradually decreases when discharging a large capacity and when discharging for a long time.

  Computers are often used as control loads, and these loads are inherently vulnerable to voltage fluctuations. However, since the DC power supply equipment has voltage fluctuations as described above, the DC bus 6 The DC control load connected to is required to be designed and designed to cope with the voltage drop due to the discharge of the storage battery 4 as described above.

Japanese Patent Application Laid-Open No. Hei 6-289189 [Patent Document 1] is cited as a patent relating to a DC power supply facility of a power plant. In JP-A-6-289189, the capacity of a DC control load is provided by providing a DC power supply equipment for a DC control load, a DC power supply equipment for a DC motor, and a DC power supply equipment for each load from the emergency low-voltage bus 1. There is provided a DC power supply facility that can flexibly cope with an increase in the number of storage batteries 4 due to the increase.

  However, the technique of the known example is a patent for the purpose of improving the response to the increase in capacity of the DC control load, and is not a countermeasure against the voltage fluctuation of the DC bus, which is currently raised as a problem.

JP-A-6-289189

  In the conventional configuration described above, it has been impossible to keep the voltage of the DC bus bar constant due to the voltage drop due to the discharge of the storage battery. Therefore, the load connected to the DC bus has to be a load that takes into account the voltage drop due to the discharge of the storage battery.

  A DC voltage regulator is installed on the output side of the storage battery to keep the DC bus voltage constant and use a standard load, but in a discharge pattern of a nuclear power plant, a large capacity discharge in a short time after the start of discharge can be considered. However, since it is necessary to correspond to the DC voltage regulator, the capacity of the DC voltage regulator is increased.

  Accordingly, an object of the present invention is to compensate for a voltage drop due to discharge of a storage battery in a DC power supply facility of a power plant, and to supply a constant voltage to the DC control load all the time. It is possible to use a standard load, and the DC voltage regulator can be installed with only a DC control load so that it can be handled with a small capacity and provide a DC power supply facility that meets the load requirements. It is in.

  In order to solve the above-mentioned problems, the present invention provides a DC power supply facility for a power plant comprising a charger, a power storage means and a DC bus for supplying power to a DC auxiliary equipment in a power plant in a power plant. One DC bus, a second DC bus for a load having a smaller transient capacity than the load, and the second DC bus to the second DC bus via the DC voltage regulator having a voltage booster and a diode from the power storage means, The voltage drop due to the discharge of the power storage means is compensated.

  Further, the present invention is characterized in that, in the DC power supply facility of the power plant, the voltage of the second DC bus is maintained by monitoring the voltage of the second DC bus and controlling the DC voltage regulator. Is.

  The present invention also relates to a DC power supply facility of a power plant that monitors the voltage of a DC control load connected to the second DC bus and controls the DC voltage regulator to control the voltage at the DC control load. Is compensated for.

  Further, the present invention is characterized in that, in a DC power supply facility of a power plant, the DC voltage regulator is installed for each DC control load, and the voltage to the DC control load is compensated.

  The present invention also relates to a DC power supply facility of a power plant that monitors the voltage of a DC control load connected to the second DC bus and controls the DC voltage regulator to control the voltage at the DC control load. Is compensated for.

  The present invention separates a DC bus into a DC motor / breaker operation load bus and a DC control load bus in a DC power supply facility of a power plant, and the DC control load bus is connected to the storage battery via a DC voltage regulator. And having a configuration for receiving power.

  By adopting the present invention as described above, it is possible to supply a constant voltage to the DC control load from beginning to end, so that a standard product can be applied to the DC control load. Further, the DC voltage regulator can be reduced in capacity by installing the DC voltage regulator exclusively for the DC control load.

  According to the present invention, in the DC power supply facility of the power plant, the DC bus is separated into a DC motor load bus and a DC control load bus, and the DC control load bus is connected to the storage battery via the DC voltage regulator. By receiving power in this manner, the voltage of the DC control load bus can be kept constant, so that a standard load can be used as the DC control load. In addition, since the direct-current control load has a small capacity, the direct-current voltage regulator can be used with a small-capacity device.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a DC power supply facility of a nuclear power plant that is an embodiment employing the present invention. FIG. 2 shows details of the DC voltage adjusting device 9.

  The configuration of the DC power supply equipment according to the present invention will be described with reference to FIGS.

  The configuration of the DC power supply equipment according to the present invention comprises an emergency low-voltage bus 1, a DC power supply power receiving breaker 2, a charger 3 connected thereto, and a DC power supply requiring a DC power supply on the output side of the charger 3. A DC bus 6 for supplying power to the load, and a second power received via the DC voltage regulator 9 from the DC motor / breaker operation load bus 7 and the DC bus 6 as the first bus that receives power from the DC bus 6. Are connected to a DC control load bus 8 and a voltage monitoring device 10 for monitoring the voltage of the DC control load bus 8 and controlling the DC voltage regulator 9. The DC voltage adjusting device 9 includes a diode 11 and a DC voltage boosting device 12 as shown in FIG. The storage battery 4 as the power storage means is normally float-charged, and becomes a DC power supply source when the entire plant AC power supply is lost.

  The DC power supply equipment is installed as a power supply to a DC control load for operation control including emergency of the plant, and as an emergency power source when the AC power supply is lost.

  During normal plant operation, the charger 3 connected to the emergency low-voltage bus 1 converts an AC power source into a DC power source and constantly charges the storage battery 4, and also includes a DC bus 6, a DC motor / breaker operation load bus 7 To supply power to a DC motor load that requires DC power during normal plant operation. On the other hand, the DC control load is supplied with power from the DC bus 6 via the DC voltage regulator 9 and the DC control load bus 8. During normal plant operation, the DC power supply is fed from the charger 3 and is therefore controlled at a voltage near the rated value. Therefore, the DC voltage booster 12 does not operate in the DC voltage regulator 9. This is because forward voltage is applied in the direction from point B to point A, and power is fed through the diode 11 due to the rectifying action of the diode 11.

  When the AC power is lost, the input power of the charger 3 is lost, so the output of the charger 3 is also lost. As a result, electric power is supplied from the storage battery 4 to supply power to a load that requires a DC power supply when the AC power supply is lost.

  FIG. 3 is a graph showing the relationship between the discharge time, discharge current, and discharge voltage in the storage battery 4 together with the configuration of the DC power supply equipment adopting the present invention, the DC motor / breaker operation load bus 7 and the DC control load bus 8. The graph which shows the relationship between discharge time and load current, and the graph which shows the relationship between the discharge time of bus-bar 8 for DC control load, and bus-line voltage are shown.

  The DC motor / breaker operating load is supplied with power from the storage battery 4 via the DC bus 6 and the DC motor / breaker operating load bus 7. As shown in FIG. 3, it can be seen that the DC motor / breaker load uses a large capacity in a short time after the start of discharging the storage battery 4. That is, since the discharge rate is high (the discharge current is large), the voltage of the storage battery 4 is greatly reduced.

  The DC control load is supplied with power from the storage battery 4 through the DC bus 6, the DC voltage regulator 9, and the DC control load bus 8. When the voltage of the DC control load bus 8 is equal to or higher than the rated voltage of the DC control load, the DC voltage booster 12 does not operate in the DC voltage regulator 9 as in the normal operation of the plant. Power is supplied.

  As shown in FIG. 3, when the voltage of the storage battery 4 decreases due to discharge, the diode 11 is activated by the action of the DC voltage booster 12 controlled by the voltage monitoring device 10 that monitors the voltage of the DC control load bus 8. , A reverse voltage is applied in the direction from the point A to the point B, so that no current flows through the diode 11 and is fed from the DC voltage booster 12 to the DC control load bus 8, and the DC control load bus 8 Is maintained constant.

  With the above configuration, the voltage of the DC control load bus 8 can be kept constant, and a standard product can be used for the DC control load.

  As shown in FIG. 3, the DC control load has a longer use time than the DC motor load, but the discharge current is small. Here, the DC voltage adjusting device 9 is composed of a semiconductor element, and a factor for determining the capacity is an energization current. Therefore, if the energization current can be reduced, the DC voltage regulator 9 can be reduced in size.

  Next, a second embodiment is shown in FIG. In this embodiment, the voltage supplied to the DC control load is monitored at the terminal of the load connection cable connected to the DC control load bus 8 with respect to the configuration of FIG. It is possible to compensate for the voltage drop. The voltage monitoring device 10 in this embodiment selects a signal having the lowest voltage from among a plurality of voltage signals from the DC control load, or selects an intermediate value, controls the DC voltage adjusting device 9, and controls DC control. Supply a constant voltage to the load.

  Next, a third embodiment is shown in FIG. In this embodiment, in contrast to the configuration shown in FIG. 1, a DC voltage adjusting device 9 is installed for each DC control load, and the voltage supplied to the DC control load is monitored at the DC control load connection cable terminal. is there. According to this configuration, it is possible to perform control corresponding to each DC control load. Further, the DC voltage adjusting device 9 can be handled by a device having a very small capacity.

  In addition, although the example used for the nuclear power plant was shown as DC power supply equipment of a present Example, it is applicable also to DC power supply equipment of a thermal power plant as a power plant.

The system circuit diagram of the DC power supply equipment of the power plant of 1st embodiment which concerns on this invention. FIG. 2 is a detailed system circuit diagram of the DC voltage regulator of FIG. 1. The figure which shows the discharge pattern of a storage battery in the system | strain circuit diagram of the DC power supply equipment of FIG. 1, the change of discharge voltage, and the discharge pattern of each bus-line. The system circuit diagram of the DC power supply equipment of the power plant of 2nd embodiment which concerns on this invention. The system circuit diagram of the DC power supply equipment of the power plant of 3rd embodiment which concerns on this invention. The system circuit diagram of the DC power supply equipment of the conventional power plant. The figure of the discharge current pattern of the storage battery of DC power supply equipment. The figure which shows the change of the discharge voltage of the storage battery of DC power supply equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Emergency low voltage bus line, 2 ... Receiving circuit breaker for DC power supply equipment, 3 ... Charger, 4 ... Storage battery, 5 ... Storage battery circuit breaker, 6 ... DC bus line, 7 ... DC motor load bus line, 8 ... DC control Load bus, 9 ... DC voltage adjusting device, 10 ... voltage monitoring device, 11 ... diode, 12 ... DC voltage boosting device.

Claims (5)

In a DC power supply facility of a power plant comprising a charger, a power storage means and a DC bus for supplying power to a DC auxiliary device in a power plant in a power plant,
A first DC bus for a load with a large transient capacity;
A second DC bus for a load having a smaller transient capacity than the load;
A DC power supply facility for a power plant that compensates for a voltage drop due to discharge of the power storage means from the power storage means to the second DC bus via a DC voltage regulator having a voltage booster and a diode. In the DC power plant of the power plant according to claim 1,
A DC power supply facility for a power plant that monitors the voltage of the second DC bus and maintains the voltage of the second DC bus by controlling the DC voltage regulator. In the DC power plant of the power plant according to claim 1,
A DC power supply for a power plant that monitors the voltage of a DC control load connected to the second DC bus and compensates the voltage at the DC control load by controlling the DC voltage regulator. Facility. In the DC power plant of the power plant according to claim 1,
A DC power supply facility for a power plant, wherein the DC voltage regulator is installed for each DC control load, and the voltage to the DC control load is compensated. In the DC power plant of the power plant according to claim 4,
A DC power supply for a power plant that monitors the voltage of a DC control load connected to the second DC bus and compensates the voltage at the DC control load by controlling the DC voltage regulator. Facility.

Images