JPH0879983A - Dc power source system - Google Patents

Abstract

PURPOSE: To suppress the charge of a storage battery by reducing the discharge amount from the battery when a charger and a storage battery system in which a spare charger are separated in a disposing manner is backed up. CONSTITUTION: An impedance 16 for compensating an electric circuit impedance and an electromagnetic switch 10 for short-circuiting the impedance 16 for short-circuiting it at the normal time are provided at the outlet of the storage battery 18 of a normal service charger 4 side. At the time of serving by a spare charger 3, the switch 10 for short-circuiting the impedance 16 is opened by the close signal 23 of the receiving breaker 8 of the charger 3 side of the charger 4. The output voltage of the charger 3 is raised by the signal 23 of the breaker 8 of the charger 4 of the charger 3 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC power supply system, and in particular, as in a nuclear power plant, a plurality of regular chargers and storage battery systems are installed at different locations due to the requirement of system separation. A DC power supply system that is suitable when a common precharger is installed.

[0002]

2. Description of the Related Art As a known example close to the present invention, Japanese Patent Laid-Open No.
The 51741 publication will be described.

Japanese Unexamined Patent Publication No. 58-51741 discloses a constant current control system, in which the time constant of the constant current control system is switched depending on the magnitude of the fault current so that the constant current control can be performed rapidly depending on the aspect of the fault. Made possible

[0004]

In a nuclear power plant, a plurality of regular chargers and accumulators are provided, and in order to maintain independence between them, they are installed at locations remote from each other.

Here, when a common preliminary charger is provided for a plurality of regular chargers, the distance between any regular charger or storage battery and the preliminary charger is inevitably long. . Therefore, when operating with a pre-charger during AC power supply and regular charger maintenance inspection during plant regular inspection, considering the pre-charger and DC load, and between the storage battery and DC load, the former distance is better than the latter distance. Since the voltage drops due to the cable of the former electric path, the storage battery shares most of the load current, and the storage battery may be discharged.

Originally, the pre-charger is a facility for supplying power to the DC load without discharging the storage battery as a backup of the regular charger, and it is desirable that the storage battery be prevented from discharging as much as possible.

An object of the present invention is to reduce the amount of discharge from the storage battery side as much as possible in the case where the precharger is arranged in parallel with the storage battery that is distant in distance and supplies electric power to the DC load. It is to provide a DC power supply system in which the charger can supply most of the power to the DC load.

[0008]

SUMMARY OF THE INVENTION The above object is to provide a direct-current power supply system comprising a plurality of regular chargers, a storage battery, and a pre-charger shared by them, and a circuit impedance between the pre-charger and the DC load at the storage battery outlet. This can be achieved by providing a resistance equivalent to the above and a circuit breaker for wiring, an electromagnetic contactor, or the like as means for short-circuiting the resistance during normal operation.

Further, the present invention can be achieved by providing a control circuit for controlling the charger output voltage with a circuit for increasing the set output voltage according to a signal indicating that the precharger is in use.

[0010]

According to the present invention, when the precharger is operated and an impedance is inserted at the outlet of the storage battery and the output voltage of the precharger is equal to the voltage of the storage battery, the current required by the DC load is the same as that of the precharger. Impedance of the circuit between the DC load: R ₂ and impedance of the circuit between the storage battery and the DC load:
Impedance inserted at R ₁ and battery outlet: R ₃
By the sum of (R ₁ + R ₃ ), (R ₁ + R ₃ ): R ₂
It is shared in inverse proportion to the impedance ratio of.

Therefore, the distance between the precharger and the DC load is long, and the impedance R ₂ between the precharger and the DC load is the impedance between the storage battery and the DC load.
When R ₂ is larger than R ₁ and R ₂ > R _1, and the share of the current required by the DC load is larger in the storage battery, impedance R ₃ is inserted at the storage battery outlet, and R ₂ <
By setting (R ₁ + R ₃ ), the share of the current required by the DC load can be increased on the precharger side.

Further, since the voltage at the DC load end: V ₁ has a single value, if the output voltage V ₃ of the precharger is increased, the impedance between the precharger and the DC load is R:
₂ and the output current of the precharger: I ₂ , the voltage drop in the electric path: I ₂ R ₂ and the voltage V ₁ at the DC load end (V ₁ + I
₂ R ₂ ) = V ₃ , and on the storage battery side, the impedance between the storage battery and the DC load is R ₁ and the output current of the storage battery is I ₁
The sum (V ₁ + I ₁ R ₁ ) of the voltage drop in the electric path due to and: I ₁ R ₁ and the voltage V ₁ at the DC load end becomes equal to the storage battery voltage: V ₂ .

(V₁＋ I₁R₁) = V_Two  Therefore, R_Two> R₁Even if V₃> V₂If so, I₂
> I₁It can be.

Further, by combining the above two methods, the output current I ₁ on the storage battery side can be further reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, it has a plurality of regular chargers 2 and 4 that receive power from an alternating current power source 1, rectify alternating current and convert it into direct current. The DC power supply system with the
Normally, the operation is as follows. That is, on the regular charger 2 side, the output circuit breaker 5 of the regular charger 2 is closed,
The output circuit breaker 12 of the storage battery 11 is closed and the power receiving circuit breaker 6 on the side of the pre-charger 3 of the service charger 2 is open. The service charger 2 receives power from the AC power supply 1 and rectifies the AC power to generate the DC power supply. And supplies the electric power to the DC load 13 on the regular charger 2 side, and keeps the voltage of the storage battery 11 on the regular charger 2 side the same as the output voltage of the regular charger 2.

Similarly, on the service charger 4 side, the output circuit breaker 9 on the service charger 4 side is closed, and the output circuit breaker 1 of the storage battery 18 is closed.
7 is closed, and the power receiving breaker 8 on the side of the pre-charger 3 of the regular charger 4 is open. The regular charger 4 receives power from the AC power source 1, rectifies the AC and converts it to a DC power source, and performs regular charging. Power is supplied to the DC load 15 on the charger 4 side and the regular charger 4
While supplying power to the DC load 15 on the side, the voltage of the storage battery 18 on the side of the regular charger 4 is kept the same as the output voltage of the regular charger 4.

In the DC power supply system configured as described above, when the precharger 3 and the regular charger 2 in the vicinity are stopped for maintenance or the like, the output breaker 5 of the regular charger 2 is opened and The output circuit breaker 7 of the pre-charger 3 and the power receiving circuit breaker 6 of the pre-charger 3 side of the regular charger 2 are closed, and the direct current of the pre-charger 3 and the regular charger 2 is connected to the DC of the regular charger 2 side. Power is supplied to the load 13. In this case, since the service charger 2 and the pre-charger 3 are both closer to the DC load 13 on the service charger 2 side than the storage battery 11 on the service charger 2 side, the power to the DC load 13 on the service charger 2 side is reduced. The supply can be replaced by the precharger 3.

On the other hand, when the regular charger 4 separated from the preliminary charger 3 is stopped for maintenance or the like, the output breaker 9 of the regular charger 4 is opened and the preliminary charger 3 and the output breaker are opened. 7. Power receiving circuit breaker 8 on the pre-charger 3 side of the regular charger 4
Closed and the storage battery 18 on the side of the pre-charger 3 and the regular charger 4 is closed.
Thus, power is supplied to the DC load 15 on the side of the regular charger 4. At this time, due to the closing signal 23 of the power receiving breaker 8 on the pre-charger 3 side of the service charger 4, the storage battery 18 on the service charger 4 side is closed.
The normally closed electrical circuit impedance compensating impedance 16 provided at the outlet is opened and the electromagnetic switch 10 for short circuit is opened, and the electrical circuit impedance compensating impedance 16 is inserted into the outlet of the storage battery 18 on the regular charger 4 side. FIG. 2 shows the above configuration by an equivalent circuit.

FIG. 2 shows a state in which the precharger 3 is supplying power to the DC load 15 on the regular charger 4 side in parallel with the storage battery 18 on the regular charger 4 side. At this time, the impedance 21: R ₂ of the cable between the precharger 3 and the regular charger 4 is between the DC load 15 on the precharger 3 side and the regular charger 4 side.
The impedance 20: R of the cable between the storage battery 18 on the regular charger 4 side and the DC load 15 on the regular charger 4 side.
₁ and the normally closed circuit impedance compensating impedance 16 The circuit circuit impedance compensating impedance 16: R ₃ inserted by opening the electromagnetic switch 10 for short circuit exists.

When the output voltage 26: V _{3 of the} pre-charger ₃ and the terminal voltage 25: V ₂ of the storage battery 18 on the side of the regular charger are equal, the storage battery 18 on the side of the regular charger 4 shares the voltage on the regular charger 4 side. Current of DC load 15: I ₁ is I ₂ · R ₂ / (R ₁ + R
₃ )

Therefore, the impedance 16: R for compensating the impedance of the electric path, which has a value such that (R ₁ + R ₃ )> R ₂
By inserting ₃ , the current I ₁ shared by the storage battery 18 on the regular charger 4 side can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 3 shows a DC power supply system. Here, when the regular charger 4 separated from the preliminary charger 3 is stopped for maintenance or the like, the output circuit breaker 9 of the regular charger 4 is opened to open the preliminary charger 3, the output circuit breaker 7, and the regular charging. The power receiving breaker 8 on the side of the preliminary charger 3 of the charger 4 is closed, and power is supplied to the DC load 15 on the side of the regular charger 4 by the storage battery 18 on the side of the preliminary charger 3 and the regular charger 4. At this time, the close signal 23 of the power receiving circuit breaker 8 on the precharger 3 side of the regular charger 4 is sent to the thyristor gate control circuit of the precharger 3 to control the thyristor control angle of the precharger 3 to perform the precharge. Increase the output voltage V ₃ of the device 3.

FIG. 4 shows the above configuration by an equivalent circuit.

FIG. 4 shows a state in which the precharger 3 is supplying power to the DC load 15 on the regular charger 4 side in parallel with the storage battery 18 on the regular charger 4 side. At this time, the output voltage V 3 of the pre-charger _{3 is set} to the terminal voltage 25 of the storage battery 18 on the regular charger 4 side:
Make it higher than V ₂ .

[0026] Here, the terminal voltage of the conventional charger 4 side of the DC load 15 24: Since V ₁ was common to both, the output current I ₂ of the output current I ₁ and the precharge unit 3 of the storage battery 18 is conventional charger 4 and the storage battery 18 on the regular charger 4 side, the impedance of the cable: R ₁ , and the impedance of the cable between the pre-charger 3 and the regular charger 4: R ₂ , V ₃ =
I ₂ R ₂ + V ₁ and V ₂ = I ₁ R ₁ + V ₁ . This relationship is shown in FIG.

Therefore, even if R ₂ > R ₁ , V ₃ > V ₂ ·
If R ₂ / R ₁ , then I ₂ <I ₁ . That is, by increasing the output voltage 26: V ₃ of the pre-charger 3, the storage battery 1
The output current I _{1 of} 8 can be reduced.

[0028]

The present invention has the following effects.

In the case of the first embodiment, when the precharger 3 backs up the service charger 4 which is separated from the precharger 3, the impedance 16 for compensating the circuit path is inserted into the outlet of the storage battery 18 on the service charging 4 side. By doing
The sum of the impedance 21: R ₁ of the cable 14 between the pre-charger 3 and the DC load 15 on the side of the regular charger 4 and the impedance 16: R ₃ for compensating the impedance of the circuit is R ₂ <(R ₁
+ R ₃ ).

Output current of precharger 3: I ₂ and storage battery 1
Since the output current of 8: I ₁ has a relation of I ₁ (R ₁ + R ₃ ) = I ₂ R ₂ , the output current of the storage battery 18: I ₂ by setting (R ₁ + R ₃ )> R _{2. Since 1} can be reduced, there is an effect of reducing the amount of discharge from the storage battery 18.

Further, in the case of the second embodiment, in the same operating condition as described above, the output voltage 26: V ₃ of the precharger ₃ is compared with the terminal voltage 25: V ₂ of the storage battery 18 on the regular charger 4 side. , V ₃ > V ₂ · R ₂ / R ₁
From the relationship of I ₂ = I ₁ R ₁ + V ₁ and I ₃ = I ₂ R ₂ + V ₁ ,
_{Since 1} <I ₂ and the output current I ₁ of the storage battery 18 can be reduced, there is an effect of reducing the discharge charge from the storage battery 18.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the direct-current power supply system having the configuration of FIG. 1 when the pre-charger backs up the service charger that is far from the distance.

FIG. 3 is a circuit diagram showing a second embodiment of the invention.

FIG. 4 is an equivalent circuit diagram of the direct-current power supply system having the configuration of FIG. 3 when the backup charger backs up the regular charger that is farther away.

5 is an explanatory diagram showing the magnitude of each voltage in the equivalent circuit of FIG.

[Explanation of symbols]

1 ... AC power supply, 2, 4 ... Regular charger, 3 ... Pre-charger,
5, 7, 9, 17 ... Output breaker, 6, 8 ... Receiving breaker,
10 ... Electromagnetic switch, 11, 18 ... Storage battery, 12 ... Circuit breaker, 13, 15 ... DC load, 14, 19 ... Cable, 1
6 ... impedance, 23 ... closed signal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Ota 3-2-1, Sachimachi, Hitachi, Ibaraki Prefecture Hitachi Engineering Co., Ltd.

Claims (3)

[Claims] 1. A common use for a plurality of service chargers that rectify an AC power source and convert it into a DC power supply, and storage batteries that are connected in parallel with the service chargers and a plurality of service chargers that are connected in parallel to each other. In the direct-current power supply system for supplying power to a direct-current load, the remote-use charger having a remote side and the preliminary charger connected to the storage battery side with a cable or the like,
When the pre-charger backs up the regular charger that is distant in location, at the outlet of the corresponding storage battery, an impedance corresponding to the impedance value of the cable from the pre-charger to the DC load or more DC power supply system characterized by inserting. 2. The output voltage of the precharger according to claim 1, when the precharger backs up a service charger that is remote in location, a cable from the precharger to a DC load, etc. DC power supply system that raises more than the voltage drop due to the impedance of. 3. The DC power supply system according to claim 1, wherein impedance is inserted into the outlet of the storage battery and the output voltage of the precharger is increased.