JPS5953037A - Method of operating dc transmission system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a DC power transmission system, and in particular to a DC power transmission system suitable for transmitting power from a nuclear power generator to a load side via a plurality of DC power transmission systems. Regarding how to drive.

Hydropower, thermal power, nuclear power, etc. are widely used as energy sources in the RRG system. Hydroelectric power plants that use hydropower as an energy source may not be able to be constructed depending on geographical conditions. Therefore, power generation using thermal power as an energy source is widely used. Fuels such as coal, oil, and natural gas are used for power generation using this thermal power as an energy source.

However, since these fuels are at risk of running out,
In recent years, nuclear power generation using nuclear power as an energy source has become popular. However, in the case of nuclear power generation 1
'1 Nuclear power plants have difficult location requirements and are often constructed far from demand areas. Therefore, when transmitting power generated by nuclear power generation to a place of demand, it is necessary to perform long-distance power transmission. In this case, there are two possible cases: AC power transmission and DC power transmission. However, when transmitting power over long distances using alternating current, there are problems such as higher line losses, problems with power transmission stability, and higher costs than when transmitting direct current. Therefore, when transmitting electricity over long distances,
DC power transmission has various advantages over AC power transmission.

FIG. 1 shows a power transmission system diagram when direct current power is transmitted.

The power transmission system shown in Figure α1 consists of a direct υIL power transmission system with two bipolar lines, and the DC power transmission system has failed. Kamoai is also designed to reduce the impact on nuclear power generators. That is, the electric power generated by the nuclear power generator 11 is passed through transformers 21, 22, 23, and 24 which are divided into four systems to AC/DC converters 41, 42, 4, which convert alternating current to direct current.
Provided at 3.44. The bulk power of AC+RI converters 41 to 44 is transmitted through DC transmission lines 61, 62, 63, 64, and 65, respectively.
．． 66, an AC/DC converter 51 that converts direct current to alternating current.
, 52°53.54. AC/DC converters 51-5
The AC 'i↓L power of 4 is supplied to the AC system 12 on the load side via transformers 31, 32, 33, and 34. AC/DC converter 41, 42, 51, 52, DC transmission line 61°62.63
Yo! 71 lines are configured, and when one of the DC transmission lines 61 and 63 has ten poles, the wire to the other DC becomes one pole. Similarly, one circuit is constituted by AC/DC converters 43, 44, 53, 54 and DC transmission lines 64, 65, 66, and if one of the DC transmission lines 64, 66 has ten poles, the other DC transmission line It becomes unipolar.

The AC/DC converters 41 to 44 and 51 to 54 are each controlled by a control device 81.
Its operation is controlled by control signals from ~88.

Further, the control devices 81 to 88 are controlled by control commands from the central control device 80.

Also, a control device 7 for controlling the operation of the nuclear power generator 11
0 is provided with a power load unbalance relay for protecting the nuclear power generator 11 from disturbances. This relay indicates that the magnitude of the output current of the nuclear power generator 11 has decreased to 40% or less of the rated current, and that 40% of this current
It works under either of two conditions: the change in occurs in 10 rn s. The nuclear power generator 1 is activated by the operation of the relay.
A so-called scram condition occurs in which the operation of the first one is stopped.

In this way, when ′+, (i, Safety measures have been taken to put the nuclear power generator 11 into a scram state and protect the nuclear power generator 11 from external disturbances. It takes several hours to several days for the transmission line to reach this state.Therefore, if the nuclear power generators are put into a scram state every time there is a failure in the power transmission system, the reliability of the transmission rfL will decrease.However, if the transmission line The longer it is, the higher the probability that a ground fault will occur.

Therefore, if the DC 61+ power transmission system is configured with two bipolar circuits as shown in Figure 1, even if one pole's power transmission is stopped due to an accident in the one pole's DC system, the output current of the nuclear power generator 11 will be Since it is reduced by only 1/4, that is, 25%, there is no need to put the nuclear power generator 11 into a scram state due to an accident in the one-pole DC system. However, even though it is called a ground fault, there are few permanent ground faults, and there are many ground faults accompanied by temporary arcs caused by 14fllF or the like.

Therefore, conventionally, ground fault i in the i/4:υIL power transmission system
'ik occurred. Sb rF, an operation is performed in which the turtle feed is temporarily stopped and restarted after allowing time for the arc to extinguish.
＋、There is.

In addition, in the case of a temporary ground fault, the ground fault can be removed in the same way as reclosing an AC system, and FL power transmission is possible.

However, if a ground fault occurs in the direct υ IC transmission system of two of the two bipolar circuits (at time t), the six-pole P+ to P4
Direct lAQ 'fQ: As shown in Fig. 2 (a) to (d), the current is two poles 7, J, '2' direct r, iU'+J
, jjir, decreases. When the operation of the faulty pole is stopped]2 (time 1.), the output current of the nuclear power generator ■l will be 2/4 at the time of 4i, as shown in (e), that is, 50
% or less. Therefore, when the output Td current decreases to more than 40% of the rated current (
11! Between i and tz), the power load unbalance relay is activated as shown in Figure 0, resulting in a scram state.

In this way, even if a DC power transmission system is constructed with 11.1 twin quadruplets and two twin cables, 1. If the output peak of the nuclear power generator drops below a predetermined value due to a failure in the iL 'Ill system, etc., the nuclear power plant 1 [f5 aircraft will be forced to enter the scram state 4, and the It will be done.

This invention '-': t1'J +j This invention was made in view of the mountainous problem, and its purpose 1J: , To improve the reliability of direct current transmission system I
Improvement of JT is 1. The object of the present invention is to provide a method of operating a DC transmission system that achieves a speed of 1/1.

In order to achieve the above object, the present invention is configured such that even a DC power transmission system can withstand temporary overload operation, so that when any system in the DC power transmission system fails, The normal DC transmission system is switched to overload operation, and through this operation the magnitude of the output current of the DC transmission system is maintained above a predetermined value, and then the power transmission of the failed system is stopped. It is characterized by what it did.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 3 shows a four-component diagram of a command value creation circuit for creating command values for the central control device 800 shown in FIG. In the figure, a command value generation circuit 800 includes a two-pole failure detection device 801, a timer 802, and switches 803 and 804.
It consists of The two-pole failure detection device wake-up 801 is 4
A device that detects faults in two poles, including ground faults in six poles,
Detection signal 1 from a failure detection device that detects arm short circuits, etc.
, 2°3.4 are supplied. These signals are i! when the 6 poles are normal f). 5m, 11f1 "0" signal, logic tt 1 in case of accident such as ground fault.
This becomes the py signal.

After a predetermined period of time from the time when the output signal of the timer 802 kJ and the two-pole fault detection device 801 becomes '1', the output becomes '1', and the output signal is supplied to the switch 804.The switch 803 is a DC 7 in the system is a switch that turns on and off the force increase 1 command, and the on/off operation of this switch is turned on when the output of the two-pole fault detection device fM801 becomes 1", and turned off when It O#. becomes. The switch 804 is a switch that turns on and off a command to stop a failure in the DC system, and this on and off operation is turned on when the output of the timer 802 is 11N. It is off when .

By the way, input signals 1, 2, and 3.4 supplied to the fM801 with a 2-pole failure are normally ``0'', but if a failure occurs, the input corresponding to 6-pole The signal is
1''. Therefore, the logic for determining a two-pole fault from the human input signal 1°2.3.4 is expressed by the following equation.

2) Nu1゛1 (Fight = 1, 2, 3, 4 + 1, 2, 3, 4 +
1, 2, 3, 4 + 1, 2, 3, 4 + 1, 2, 3, 4 + 1
・2・3・4nafu・・・ is ant (logical score), 10 is Oi
t (Logic 411), - is the anti-1 Akane Dip number.

Here, in the case of 1, 2, 3, and 4, the logic circuit has an 11.v configuration as shown in FIG. That is, the input signal 3 and the input signal 4 are connected to the inverter 8 in the case where the two-pole failure has occurred.
16 inverted with 01A and 801B, and human power signal 1 and human power signal 2 by ant game) 801C, it is possible to create a volcano.

Therefore, the operation of the command value generation circuit 8000 when a two-pole fault detection device 801 detects a two-pole fault detection circuit 8000 will be explained based on FIG.

As shown in FIGS. 5(a) and 5(b), if a ground fault occurs at time to, a two-pole fault detection device 1ffi 801 detects a two-pole fault at time t1. When a two-pole failure is detected at time 11, switch 803 is turned on and an overload operation command is output to the healthy pole. Therefore, the 1συ1 current of the healthy pole is (
C), (rises as shown in (1).The magnitude of this output 'iii flow is due to the fact that the atomic blade base-14111 is in a scram state due to overload operation of the two poles in the 4.
! clni is set to the value that stops it. Therefore,
As shown in (e), the magnitude of the output current of the atomic blade source';d4Q 11 is maintained within 40% of the rated current '1d.

After a certain period of time t3 after the overload operation of the healthy pole, the output of the timer 802 becomes °゛1'', and the switch 8
04 is turned on. As a result, the failed pole (operation is stopped).

As described above, in this embodiment, even if two of the four poles are in one pupil, the output of the nuclear power generator 11 will not decrease to more than 40% due to overload operation due to the healthy pole. Therefore, even if two of the four poles are 1+t2), the Q's starting machine will not be in a scrum state, so the reliability of the transmission will be improved.

In addition, if the ground fault on the transmission line 71j is temporary,
When it becomes possible to restart the other 11 motors, the healthy pole's overworked Lf, +'jff rotation is stopped and normal operation is started. In addition, many ground faults are temporary, and if the arc can be removed with nitric acid (restarting can be done simply by f)ri.

In addition, in the 1) q example, we have described the case where the DC transmission system is constructed with two bipolar circuits in 11.1, but it is not limited to two bipolar circuits; Even if one of the systems in the DC transmission system malfunctions or is repaired, it is possible to prevent the nuclear power generator from reaching a scram situation due to normal overload operation of the DC transmission system. , this embodiment can be applied.

FIG. 6 shows an i#j diagram as another embodiment of the present invention.

In this embodiment, it is detected that an overload operation has been performed from the Fd flow actually flowing in the 1α flow system, and the μ? , [This embodiment differs from the previous embodiment in that the poles are stopped. That is, 6-pole DC-current detectors 811, 812, 813, and 814 for detecting direct 1>iE current are connected to the DC power transmission line 6, respectively.
1, 62, 63, and 64. Further, the command value creation circuit 800 includes an addition circuit 806 that adds the 6-pole II current values, a switch 807 that opens and closes according to the output of the 2-pole failure detection device 801, and the output of the S+n-i'1 circuit 806 and the 2-pole fault The level ratio 'i (!2'?) which reduces the output of the 11·F detection device 801 by one ratio is set by the rhinoceros 808.

According to the above (1' configuration), when a 21 fault is detected by the 2-pole fault pupil extractor δ801, the switch 803 is turned on, and the overload operation is started to increase the DC current of all other 11!I! At this time, the switch 807 is also turned on. When the total I'll of the DC type bits supplied to the arithmetic circuit 806 exceeds the level setting value of the level comparator 808, the level comparison is performed. The switch 804 is turned on by the output signal from the circuit 808, and the faulty pole is turned on.
A stop command is output to stop the installment. Note that the level setting value of the level comparator 808 is such that the sum of the direct currents supplied to the adding circuit 806 is equal to
It is set to correspond to a value exceeding 60% of the rated value of the output current of No. 1.

In this way, in this embodiment, when the healthy pole is overloaded due to the two poles 11ri, this! After it is detected that the output current of the nuclear power generator is maintained at a predetermined value or higher by the 14-load operation, the failed pole is shut down, so that 34-volt operation can be performed with higher reliability.

In each of the above embodiments, it has been described that the two faulty poles are stopped at the same time, but it is not necessary to stop them at the same time, and they may be stopped separately. For example, the same effect as in the above embodiment can be obtained by stopping only one pole after overload operation with a healthy pole, restarting this faulty pole, and then shutting down one pole of the crosspiece. It will be done.

As explained above, according to the present invention, even if a failure occurs in the DC power transmission system, it is possible to reduce the frequency of placing nuclear power generators in a scram state, which has the advantage of improving transmission in (δ reliability). It has a positive effect.

[Brief explanation of drawings]

Figure 1 is a configuration diagram when the power transmission system for nuclear power generation has two bipolar circuits, and Figure 2 shows the operation of a three-station system in which two of the four poles of the circuit shown in Figure 1 have failed. , FIG. 3 is a circuit diagram for creating a command value for a central control device showing an embodiment of the present invention, and FIG. The final diagram, FIG. 5, shows the circuit shown in FIG. 3, and FIG. 6 shows the circuit shown in FIG.
It is. 11... Nuclear power generator, machine, 41-44', 51-5
4...AC/DC converter, 61~6G...+tf flow Ia
Line, 70... Control 11141 Device, 80... (1) Width control device: Q%81-88... Control device, 800...
・Command value creation circuit, 801・" 2 i'Jξ Failure detection device, 802...Timer, 803, 804゜807・
. . . Switch, 806 . . . Addition circuit, 808 . . . Level ratio 1 unit, 812 to 814 . - Agent Patent Attorney ± 1昂4j1δMeishungil Country 6I Kaya 2 Figure'lo tlf,z Ginko-← Kaya 3 Kuchikay4th/5th (J (e)

Claims (1)

[Claims] 1. Electric power from a nuclear power generator is transmitted to the load side via multiple DC transmission systems, and when the magnitude of the output current of nuclear power generation (years) falls below a predetermined value due to a failure in the DC transmission system. In an operating method for a nuclear power generation power system in which the operation of a nuclear power generator is stopped, when any of the DC transmission systems has a failure, the normal DC transmission 'Ijj system is switched to an overload transmission operation, and this operation is stopped. 11. A method of operating a DC power transmission system, characterized in that the magnitude of the output type 6f of the nuclear power generator is maintained above the predetermined value, and then the power transmission of the failed system is stopped.