JPS58103826A - Controller for 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] In the case where a trouble occurs in which power transmission capacity is lost at any pole, ◆In order to cover several types of transmitted power, the transmitted power of one healthy pole is increased and the overall power is increased. The present invention relates to a control device for a DC power transmission system designed to suppress changes in transmitted and received power as much as possible.

For example, in the case of a two-terminal power transmission bipolar Sakaki system, the DC power transmission system is as shown in FIG. That is, in FIG. 1, A. B is an AC system connected to electric station bus lines BU81 and BUS2, Tr 1 and Tra 2.

Trml * Trl2 is the converter transformer, VAl *
VA2, Vl1+Vl2 are converters, DCLAI
, DCLa2, DCLml, and DCLl2 are DC reactors, DLl e DL2 is a DC line, and DN is a neutral wire. Also VGCA 1, VGC4 2
, VGC 1.

VGCA2 is a converter f-)/9rus control device, which operates each converter according to commands from a DC power transmission control device (not shown).

In a DC transmission system with such a configuration, there are two
When each pole operates independently of the other, if one pole becomes unable to transmit power due to a fault in the transmission line, the total transmission rate at that time will be 50% of that before the accident. Therefore, in this case, if the AC system is at the generating end and the other AC systems are not blocked, the frequency will rapidly rise, and in the worst case, a power trip will occur. Furthermore, if the AC system A is a nuclear power plant, it is conceivable that a scram may occur due to a rise in reactor pressure. Therefore, in order to avoid such problems, it is conceivable to increase the amount of healthy ultra-fine transmitted power within a margin that includes the overload capacity, thereby suppressing the cost of transmitted power. This is called healthy pole load transition.

Here, the concept of control for performing a healthy pole load shift will be explained with reference to an example of a two-terminal power transmission system having a two-pole, two-pole, and four-pole configuration shown in FIG. In Figure 2, A, B
is electric station bus line BUB1.

AC system connected to awgh2, Tral~Tr, A4
e Tyll~Tr ro is the converter transformer, Vmu 1~V
4 r Vl l to Vl4 are converters. Also DC
Lm1 to DCLm4, l) CLml-DCIJ4 is an i* fit reactor, DLI to DL4 are DC lines,
DN1tDN2 is a neutral wire.

Therefore, in such a two-terminal power transmission system, when various converters are currently operated with a four-pole equal-negative distribution, if a failure occurs in one pole, then...

The total power transmission capacity is reduced to 75% of that during 4-pole equal load distribution operation. Therefore, if the healthy pole load transfer control increases the transmitted power to 133% of the power transmitted before the accident, the decreased amount will be covered, and the transmitted power seen from the AC system will return to its original value and remain unchanged. It will be driven.

By the way, a control device for a DC power transmission system is basically a hierarchical control system as shown in FIG. That is, in FIG. 3, area [1] is the common control unit;
This is the part that performs operation commands and collective control for the entire system.In terms of control, it has the function of receiving the total operating power request of the system and distributing it to the individual poles. In a 3-terminal system or a multi-terminal system with more than 3 terminals, this part is essential and also performs the calculations necessary for the operation of each of the 6 terminals. CC indicates a DC system common arithmetic and control unit for this purpose, and R*tld indicates a total operating power request command input to this common arithmetic and control unit CC.

Region [2] is a pole control section that performs calculations within each pole.

PCI to PC4 indicate six-pole polar operation control devices.

The final part [3] is a group control section which receives the signal from the pole control section [2] and generates a phase noggle signal for controlling the converter. GCl" (1 near to 4.J: 1 to 2) indicates the rounding control device. Area [4] is the f-) pulse control section of the converter, and VGCB (1: 1~4°J: 1~
2) is a ) f − ) norus control device.

In a control device for a DC power transmission system having such a configuration, conventionally considered load transfer control sends a failure detection signal to a common arithmetic and control unit C-CKSi11), where the total transmitted power command R0
If the value of f is a healthy pole, for example, the faulty pole is the P1 pole of the second WA, it is calculated to be distributed to the healthy pole PhP4, the load is redistributed, and the output is sent to the pole calculation control device of each pole. This is a method of increasing the transmitted power of healthy poles P2 to P4 by giving it to PC2 to PC4. However, the common arithmetic and control unit C-C is often connected to each pole arithmetic and control unit PCI to PC4.
Since the common arithmetic and control unit C-C and each pole arithmetic and control unit PCI to PC4 must be connected by a signal transmission means, the control may be slow and reliable. There is a problem of decreased sexuality.

The present invention has been made in view of this problem, and when an accident occurs at any pole in a DC power transmission system having multiple operating poles and power cannot be transmitted, an accident detection signal is sent to the other healthy poles. It is an object of the present invention to provide a control device for a DC power transmission system with high axis flexibility, which can increase transmitted power over a long distance based on the signal.

An embodiment of the present invention will be described below with reference to the drawings. Fourth
The figure shows an example of the configuration of a control system in the apparatus of the present invention. In Figure 4, C-C is the command value ΣP of the total transmitted power
dp is given, and this common arithmetic and control device C-C is given a six-pole operation command value knΣPdpn (m
l: J to 4, an auxiliary symbol representing any other) is calculated.

APR1 to APR4 are constant power control circuits to which the nine various operation command values kIIΣPdpn calculated by the common arithmetic and control unit C-C are individually added, and the actual power value Pdn (n: 1 to 4) of the pole is added to each one. These constant power circuits APR
1 to APR4 are the seed operating current command values Idpm (
o: 7 to 4). Also ACRi~
ACR4 is a constant current control circuit into which the seed operating current command value Idpn output from the constant power control circuits APR1 to APR4 is input. These constant power control circuits PRi to APR
4 and constant current control circuits ACRI to CR4 are provided in the pole calculation control device'('a) of each pole.

FIG. 5 shows an example of the internal configuration of the constant power control circuits PRi to APR4. In FIG. 5, K is an r-in switching circuit to which the power residual value Pdpi from the common arithmetic and control unit C-C and the failure detection signal r of the other pole are input; When there is no F, r in 11#,
When there is a failure detection signal F, set r-in to "4"(' to 'D
> 1) and outputs the power command value. L is a limiter circuit that limits the power command value input through the r-in switching circuit K to a value that does not cause the equipment to operate at more than the allowable power, and C is the power command value applied through the limiter circuit and its polarity. Comparison (b) circuit for comparing the tortoise force detection smoke Pdn and extracting the difference, AMP is an error amplifier that amplifies the difference signal output from this comparison circuit C, and its output is the output of the constant current control circuit MORmm. It is used as a command value.

Next, the operation of the DC power transmission system control device configured as described above will be described. Now, the dual Ii 2 line 4 shown in Figure 2
In a two-terminal power transmission system with a pole configuration, all poles P1 to P
4 is operating in a healthy state, the total transmitted power command value ΣPdp at that time is the common arithmetic and control unit C-C.
K is given. Therefore, this common arithmetic and control device C-C calculates the operation command value knΣpd, (=pdp, ) for the six poles in addition to the total transmitted power command value ΣPdp, and the output of the husband and wife is sent to each of the six arithmetic and control devices. Constant power control circuits APR, (1: I to 4) K are given in fPcJ to PCd.

In this constant power control circuit APR, this operation command value Pdp
The signal is input to the comparator circuit C through the nt'f input switching circuit and a limiter circuit. In this case, in the r-in switching circuit,
Since the failure detection signal F from the other pole is not input to the terminal, its r-in is "1", and the input value and the output value are equal. The comparison circuit C compares the power command value p, 1□ with the actual power command value Pdn of the pole, and provides the difference signal to the constant current control circuit CRn as the command value Idpn of the seed operating current.

Therefore, each type of converter has a constant current control circuit A of its pole.
Multi-phase control is performed according to commands from the CR, and DC power transmission operation is performed.

When operating under such conditions, if a failure occurs in one of the poles, for example, the P1 pole, the transmitted power of the PI pole will decrease step by step, so the other health values P2 to P3 will immediately change to the next one. It enters load transfer control like this. That is, when constant power control circuit PRnK: operation command value Pdpn is input from common arithmetic and control unit CC, this operation command value Pdpm
Since the failure detection signal r is input to the r-in switching circuit K from the other pole, its gain is switched by -4''K, so when it passes through the r-in switching circuit K, it becomes 'm (k
'n > 1) Pdpm K changes. Furthermore, the operation command value obtained through this r-in switching circuit K is
Pdpn is limited by passing through a limiter circuit so that the operation does not exceed the stored power of the equipment, and is compared with the actual power detection value Pdn of that pole, and the difference signal is determined through the error amplifier fAMP. Current control circuit AcRn1/
C. Therefore, the pole operating current command value Idpn applied to the constant power control circuit PRn is the constant current control circuit CR.
, K, the converters of each health value are controlled in the direction of increasing the transmitted power, and load shifting is performed.

If this kind of load transfer control is used, the common arithmetic and control unit C
Even if the power command value Pdpn from -C is not changed, the input command to the constant power control circuit APR is apparently 'n times larger.
The pole transmission power 4 increases to 'n*, which results in K. here,
In Figures 2 and 4, if the load is distributed equally to each pole, then P
If a failure occurs in one pole, all that is required is to set the settings of the various gain switching circuits so that the sum of the settings is 4.

In this case, if the various gain settings are equal, then 'n-
It becomes 1,33.

Figure 7 shows the KP during power transmission in each extreme load distribution in Figure 2.
9 is a time chart showing various types of transmitted power and total transmitted power when the power transmission capacity is lost at the I pole and the load is shifted to the healthy value. ζIn this case, various gain settings are set to the same value. 9 fault detection time #i is ignored rounding to simplify the explanation. In the Cocoon 7 diagram, when a failure occurs in the P1 pole at time 11, the other pole immediately enters load transfer control, but at a rounded rate where the transmitted power of the P1 pole gradually decreases, and at a healthy price, it takes some time for the transmitted power to increase. It takes. The rounded total transmitted power will be temporarily reduced.

However, time 1. When the load transfer control is completed, the total transmitted power returns to its original value. By restarting the P1 pole at time t1 and resetting the gain switching circuit K of the other pole, the transmitted power is returned to its original foreshadowing at an appropriate rate of change. Time t4 indicates that all operations are completed and the state returns to the state before the accident.

In the configuration example of the constant power control circuit APRn shown in FIG. 5, the r-in switching circuit K is provided on the power setting input side, but this r-in switching circuit K may also be provided on the actual power detection signal input side of the comparison circuit C. The same effects as those described above can be obtained. In this case, the gain when the failure detection signal F is input from the other pole to the gain switching circuit is set to a value smaller than 11''. As shown in the figure, "n(k'n>1)
Pdpn Pdn=Pdpn k”n (li'n
<1) Pdn may be used.

FIG. 6 shows a constant power control circuit P with a configuration example different from that in FIG. 5.
This indicates Rn. In FIG. 6, AND is an AND circuit in which the power command value Pdpn is applied to one input terminal and the failure detection signal F from the other pole is applied to the other input terminal, and Kl is the power command value Pdpn output from the AND circuit AND. 247 circuits, ADD is the sum of the output mold/Pdp obtained from this r-in circuit m and the power command value Pdpi (Pd
pn + k” Psn), this addition xt
Each component after the m-way DD is the same as in FIG. 5.

Therefore, even in the constant power control circuit APRII having such a configuration, the power value to be increased by itself or others in the event of an accident at the other pole is calculated from the command value input signal, and the original power command mKjJl is calculated. The same effects can be obtained as in the case of

In the above explanation, a signal level conversion circuit such as an r-in switching (b) path is added to the power command value input side or the actual power detection input side in the constant power control circuit. By adding it to the constant current control circuit ACRn based on this idea, the same effects as described above can be obtained.

Although the embodiments described above are applied to a two-terminal DC power transmission system, the present invention can be similarly applied to a multi-terminal system having three or more terminals. In this case, in a multi-terminal system, the constant power control system and the constant current control system are not included in the common calculation unit, and if they are included in the pole control side, the 6-pole constant power control circuit or constant current control system of the husband's terminal A signal level conversion circuit as described above may be provided on the signal input side of the control circuit, and the same can be said of adding a limiter circuit. Furthermore, the present invention can be similarly applied to a DC power transmission system that is composed of a plurality of bipoles and is operated in bipolar units.

As described above, according to the present invention, when an accident occurs at any pole in a DC power transmission system having a plurality of operating poles and power cannot be transmitted, an accident detection signal is given to the other healthy poles, and the signal is used to transmit the power. Since the transmission power is increased rapidly, there is no need to redistribute the load using the common arithmetic and control unit and transmit the output to the six-pole seed arithmetic and control unit, as in the conventional case, and the load can be increased by that amount. 3. We can provide a control device for DC power transmission systems that can perform highly reliable control in situations where transition control is far away.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a DC power transmission system with a two-terminal power transmission and two-pole configuration.
Fig. 2 is a diagram showing a two-terminal power transmission system with a bipolar 2-time MI4 healthy configuration, Fig. 3 is a hierarchical control system configuration diagram showing the basic control device of a DC transmission system, and Fig. 4 is an implementation of the device of the present invention. FIG. 5 is a block diagram showing the configuration of a constant power control circuit in the same embodiment; FIG. 6 is a block diagram showing the configuration of a constant power control circuit in another embodiment of the present invention. , FIG. 7 is a diagram showing a time chart for explaining a state in which the load shifts to a healthy pole in the case where the power transmission capacity of one pole is lost in FIG. 2. M, B... AC system, Vm1 to Vm4. ■1~v,4
...Converter, DLl to DL4...DC line, DNl
, DN2...neutral line, C-C...common arithmetic and control device, PC1 to PC4...species arithmetic and control device, GCij
...phase control device, vGij...f −) yJ?
Luss control device, APRll... Constant power control circuit, MuC
a, constant current control circuit, K... gain switching circuit,
L...limiter circuit, C...comparison circuit, ■...-
Difference Ang, AND...AND circuit, ADD...Addition circuit.

Claims (4)

[Claims] (1) In a busy DC power transmission system with multiple operating poles, a constant current control circuit and a constant power control circuit are provided for each operating pole to control the deviation between the operating command value and the actual power detection value. A seed arithmetic control device that initially controls the operation, and a common calculation in which the total power command value of the DC transmission system is input and is distributed to individual @s and given to the various seed arithmetic control devices as the operation command value. and a control device, the operation command value signal input side or the collected power detection value input IK of the constant power control circuit or constant current control circuit of the various seed calculation control devices, and the input signal level versus output signal level is set in advance. A signal conversion circuit is provided to change the signal according to the ratio or value, and a plurality of 2! I! When part or all of the transmitted power is lost due to an accident or other cause at any of the polarity reversals, the detection signal is given to the signal level conversion circuit of the healthy pole to perform constant power control circuit or constant current control. A control device for a DC power transmission system that changes the input signal level of the circuit and controls the power transmitted to a healthy node to increase. (2) The control device for a DC power transmission system according to item (1), wherein each of the plurality of operating poles is composed of bipoles and is operated in units of bipoles. (3) In a DC transmission system having multiple operating poles, each operating pole is provided with a constant current control circuit and a constant power control circuit, and the deviation between the operating command value and the detected actual power value of that pole is a common arithmetic control device that receives the total power command value of the DC power transmission system, distributes it to individual poles, and supplies it to the various seed arithmetic control devices as the operation command value; and a preset ratio of the human power signal level to the output signal level on the operation command value signal input side or back power detection value input side of the constant power control circuit or constant current control circuit of the various types of arithmetic and control devices. Alternatively, a signal level conversion circuit is provided to change the signal level according to the value, and a limiter circuit is provided to limit the signal input level of the constant power control circuit or constant current control circuit, and a limiter circuit is provided to limit the signal input level of the constant power control circuit or constant current control circuit. When part or all of the transmitted power is lost due to an accident or other cause at one of the inner poles, the detection signal is given to the signal level conversion circuit of the healthy pole to control the constant power control circuit or the constant current control circuit. 1. A control device for a DC power transmission system, characterized in that the input signal level is changed and the limiter circuit controls the transmitted power of that pole to a permissible value so that the transmitted power of a healthy pole increases. (4) Claim (3) wherein each of the plurality of operating poles is composed of bipoles and is operated in bipolar units.
A control device for a DC power transmission system as described in paragraph 1.