JP6791749B2 - DC power transmission system and its control device - Google Patents

Description

The present invention relates to a DC power transmission system in which a power generation system such as a renewable energy power source is connected via a power conversion station and a DC power transmission line, and a control device thereof.

In recent years, an offshore DC power transmission system that collects the power generated by a plurality of wind turbines installed offshore at an offshore substation and transmits the power to land via a DC power transmission system has attracted attention.

In long-distance power transmission and submarine power transmission, a DC power transmission system is often used to improve efficiency, but since a general power system such as a wind power generator is an AC system, it is necessary to transmit power to the DC power transmission system. , It was necessary to convert the power of the AC system into DC by a power converter and then transmit the power (for example, the abstract of Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-80354

In Patent Document 1, as shown in FIG. 1 of the same document, in a DC transmission system in which at least one power generation system is connected to a forward converter and a power receiving system is connected to an inverse converter, the DC transmission system When the DC voltage exceeds a certain threshold, the forward converter is made to perform a protective operation that lowers the AC voltage on the forward converter side of the DC transmission system, and the amount of invalid power supplied from the power generation system is increased accordingly. By causing the power generation system to perform the increasing stabilization operation, the operation stoppage (also referred to as “trip”) of the power generation system due to the protective operation of the forward converter is avoided.

However, when the DC voltage rise rate of the DC transmission system is fast, even if the protection operation and the stabilization operation are executed after the threshold value is exceeded, the DC voltage rise cannot be suppressed due to the delay in communication and control of each device. There is a possibility that the DC transmission system may be shut down before the power generation system is shut down, and there is a problem that the transmission path from the power generation system to the power receiving system is cut off.

Therefore, in order to solve the above problems, the present invention comprises a power generation system that generates power, a first power conversion device that converts input power from the power generation system into DC power, and the first power conversion device. A DC / AC power conversion device that converts input DC power into AC power, a DC transmission line that connects the first power conversion device and the DC / AC power conversion device, and a DC voltage of the DC transmission line are detected. A DC transmission system including a DC voltage detection device for controlling the DC voltage and a control device for controlling the power generation system based on the output of the DC voltage detection device. The control device is a DC detected by the DC voltage detection device. The first protection control is executed when the time change rate of the voltage exceeds the first threshold value, and the second protection control is executed when the DC voltage detected by the DC voltage detection device exceeds the second threshold value. Run.

According to the present invention, even when the DC voltage of the DC power transmission system suddenly rises, the protection control can be quickly executed, the operation of the DC power transmission system can be avoided, and the operation can be continued.

The system conceptual diagram of Example 1 is shown. The conceptual diagram at the time of the DC voltage rise with the decrease of the power transmission capacity to the electric power system in Example 1 is shown. The operation characteristic diagram of the AC / DC power conversion apparatus and the power generation system of Example 1 is shown. The system conceptual diagram of Example 2 is shown. The system conceptual diagram of Example 3 is shown. The system conceptual diagram of Example 4 is shown.

Hereinafter, examples of the present invention will be described together with the drawings. The following examples show one embodiment of the present invention, and the present invention includes other embodiments as long as the gist is not deviated.

First, the DC power transmission system 100 of the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

In the DC transmission system 100 of this embodiment, the AC power generated by the AC power generation system 101 such as a wind power generation system installed offshore is converted into an AC / DC power conversion device 103 (AC) installed close to the AC power generation system 101. -Converts to DC using a DC power converter), transmits over a long distance, and then converts from DC to AC using a DC / AC power converter 104 (DC-AC power converter) installed on land. The AC is transmitted to the power system 105, and when the DC voltage of the DC transmission system 100 rises, the operation of the DC transmission system 100 can be avoided and the operation can be continued.

FIG. 1 is a conceptual diagram of the DC power transmission system 100, in which an electric circuit is shown by a solid line and a communication path is shown by a dotted line. As shown here, the DC transmission system 100 includes an AC power generation system 101, an AC bus 102, an AC / DC power conversion device 103, a DC / AC power conversion device 104, a power system 105, a power generation system group control device 106, and DC transmission. It is composed of a protection control device 107, an AC voltage detection device 108, a power detection device 109, a DC voltage detection device 110, an AC transmission line A111, an AC transmission line B112, a DC transmission line 113, and an AC transmission line C114. Hereinafter, each configuration will be described in detail.

Each of the plurality of AC power generation systems 101 is electrically connected to the AC bus 102 via the AC transmission line A111, and the AC bus 102 is electrically connected to the AC / DC power converter 103 via the AC transmission line B112. Is connected. Further, the AC / DC power conversion device 103 is electrically connected to the DC / AC power conversion device 104 via the DC transmission line 113, and the DC / AC power conversion device 104 is a power system via the AC transmission line C114. It is electrically connected to 105.

The AC voltage detection device 108 detects the AC voltage _Vac of the AC bus 102 and transmits it to the DC transmission protection control device 107. Further, the power detection device 109 detects the input power PG1 flowing through the AC power transmission line B112 and transmits it to the DC power transmission protection control device 107. Further, the DC voltage detection device 110 detects the DC voltage _Vdc of the DC transmission line 113 and transmits it to the DC transmission protection control device 107.

The AC / DC power converter 103 and the DC / AC power converter 104 are power converters generally called self-excited AC / DC power converters, such as a two-level converter and a modular multi-level converter configured by using a self-extinguishing element. In addition to equipment, it consists of electrical equipment such as transformers, breakers, and protective equipment, as well as sensors, control devices, and communication equipment.

The power generation system group control device 106 is a control device that centrally controls the AC power generation system 101, and is provided with an intercommunication means with the AC power generation system 101 to monitor the operating state of the AC power generation system 101 and to the AC power generation system 101. Sends the operation command and operation point of. Further, the DC transmission protection control device 107 controls the protection of the entire DC transmission system 100 based on signals from the AC voltage detection device 108, the power detection device 109, the DC voltage detection device 110, and the like in an emergency such as an accident. It is a control device to perform. The DC transmission protection control device 107 detects three state quantities of the DC voltage V _dc , the input power PG 1, and the AC voltage V _ac , and gives a command to the AC / DC power conversion device 103 and the power generation system group control device 106. However, it may be provided with means for detecting a state amount other than the above and for communicating with other control devices and devices.

Here, the power flow in the steady state will be described with reference to FIG. In the steady state, the AC power generated by the AC power generation system 101 is once converted to DC by the AC / DC power conversion device 103 and transmitted to the DC transmission line 113, and then converted to AC again by the DC / AC power conversion device 104. Then, it is transmitted to the power system 105. If the loss of each device and the transmission line is ignored, the size of the input power PG1 before the power conversion and the output power PG2 transmitted to the power system 105 after the power conversion are almost the same, and at this time, the DC transmission line 113 The DC voltage V _{dc in the above} is kept substantially constant.

On the other hand, the voltage of the AC transmission line C114 drops to zero due to the influence of lightning, etc., and the operation continuation control when the DC voltage _Vdc of the DC transmission line 113 rises due to the decrease in the transmission capacity to the power system 105. Will be described with reference to FIGS. 2 and 3.

FIG. 2 shows (a) the voltage of the AC transmission line C114, (b) the input power PG1 and the output power PG2, and (c) DC transmission when the transmission capacity to the power system 105 is reduced due to an accident such as a lightning strike. It is each conceptual diagram of the time change of the DC voltage V _dc of the electric wire 113 and (d) the AC voltage V _ac of the AC bus 102, the vertical axis shows the size of each element, and the horizontal axis shows time. Both the vertical axis and the horizontal axis are expressed in arbitrary units (arbitrary unit, hereinafter referred to as "au").

In FIG. 2, the time T0 is the time when an accident such as a lightning strike occurs, the state before this is the steady state, and the time after this is the unsteady state. In this embodiment, two protection controls, a first protection control and a second protection control, which will be described later, are carried out in order to continue the operation of the AC power generation system 101 even in the unsteady state. Hereinafter, the time T1 is the time when the first protection control is started, and the time T2 is the time when the second protection control is started.

In the steady state before time T0, the voltage of the AC transmission line C114, the input power PG1, the output power PG2, the DC voltage V _dc , and the AC voltage V _ac are all 1.0 [au].

In the unsteady state starting from time T0, as shown in FIG. 2A, the voltage of the AC transmission line C114 drops to 0.0 [au]. Further, as shown in FIG. 2B, the input power PG1 does not change, but the output power PG2 decreases to 0.0 [au] as the voltage of the AC transmission line C114 decreases. That is, the input power PG1 becomes larger than the output power PG2.
(First protection control)
Next, the first protection control implemented at time T1 will be described. In the time zone from time T to time T1 before the start of the first protection control, since the input power PG1 is larger than the output power PG2, the difference power is the AC / DC power conversion device 103 and the DC / AC power conversion device 104. , DC voltage V _dc of the DC transmission line 113 rises as shown in FIG. 2C as a result of being stored in the capacitance components of each of the DC transmission lines 113.

At this time, the DC transmission protection control device 107 detects the DC voltage V _dc via the DC voltage detection device 110, and calculates the time change rate dV _dc of the DC voltage V _dc . This time change rate dV _dc is calculated by, for example, (Equation 1).

V _dc [T]: Detected value of DC voltage V _dc at time T V _dc [T-ΔT]: Detected value of DC voltage V _dc before time T by ΔT Note that ΔT in (Equation 1) is the present. It can be arbitrarily set within a range that does not deviate from the gist of the invention, and if ΔT is shortened, there is a concern that the influence of noise contained in the detection system of the DC voltage V _dc will increase. In this case, the DC voltage V _dc Instead of using the detected value of (Equation 1) as it is, it is possible to eliminate the influence by performing noise reduction processing such as a low-pass filter.

When the time change rate dV _{dc at} times T0 to _T1 is larger than the predetermined threshold dV _{dcth in} the DC power transmission protection control device 107, the DC power transmission protection control device 107 sets the power generation system group control device 106 to the accident occurrence flag. The power command value PG1 _ref during the accident used when it is desired to match Flg with the input power PG1 and the output power PG2 is transmitted. In the following, the description will be continued by taking the case where the power command value PG1 _ref during the accident is set to 0.2 [au].

When the time change rate dV _dc (gradient of the DC voltage V _dc ) at times T0 to T1 shown in FIG. _2C is larger than the threshold value dV _dcth , the DC transmission protection control device 107 sends the accident occurrence flag Flg and the power command value PG1. _The power generation system group control device 106 that received _ref (0.2 [au]) calculates the operation command value of each AC power generation system 101 based on the operation state of the steady state AC power generation system 101, and each AC power generation. It is transmitted to the system 101. As a result, normally, the input power PG1 and the output power PG2, which are the sum of the power generation of each AC power generation system 101, match, so that the operation of the AC power generation system 101 can be avoided.

Regarding the calculation method of the operation command value, for example, the AC power generation system 101 is ranked in advance based on the magnitude of the generated power of each AC power generation system 101 before the accident, and the input power PG1 = power command value PG1 _ref. It is conceivable to create an operation command value so as to reduce the generated power in order from the one with the largest generated power so as to satisfy the above conditions. Regarding the control of the generated power of the AC power generation system 101, it is effective not only to continuously control the generated power but also to perform an emergency disconnection.

In this embodiment, the generated power of each AC power generation system 101 may be controlled by the power generation system group control device 106 so as to satisfy the input power PG1 = power command value PG1 _ref, and a specific operation command value is calculated. The method is not limited to the above method.
(Second protection control)
As described above, normally, by implementing the first protection control, the input power PG1 and the output power PG2 match, and the DC voltage _Vdc is kept constant. Therefore, the operation of the DC transmission system 100 is performed. Stopping is avoided, but under certain conditions, the input power PG1 and output power PG2 do not match even if control is performed based on the power command value PG1 _ref , and if left as it is, the DC voltage _Vdc of the DC transmission line 113 rises. In some cases, the DC power transmission system 100 may stop operating. In order to avoid this, in this embodiment, the first protection control is executed and then the second protection control is executed under certain conditions. Hereinafter, this second protection control will be described in detail.

As illustrated at times T1 to T2 in FIG. 2B, when the input power PG1 and the output power PG2 are not equal even by the first protection control, the influence of the capacitance component included in the DC transmission line 113 and the like. As a result, the DC voltage V _dc continues to rise. In the case of FIG. 2B, since the output power PG2 = 0.0 [au] with respect to the input power PG1 = 0.2 [au], the DC voltage _Vdc rises as shown in FIG. 2C. If left unattended, the operation of the DC power transmission system 100 will be stopped.

Therefore, even after starting the first protection control, the DC voltage V _dc is monitored, and when this becomes larger than the predetermined threshold value V _dcth , the second protection control is started. In this embodiment, the threshold value V _dcth = 1.1 [au] is set in advance, and the second protection control is performed at the time T2 when the DC voltage V _dc reaches 1.1 [au], that is, FIG. The control of increasing the AC voltage _Vac input to the AC / DC power converter 103 according to the amount of increase of the DC voltage V _{dc from} the reference value shown in d) is started.

Here, the operating characteristics of the AC / DC power conversion device 103 and the AC power generation system 101 will be described with reference to FIG. The left figure of FIG. 3 is an operation characteristic diagram of the AC / DC power converter 103. The vertical axis represents the change width ΔV _ac from the reference operating point of the AC voltage V _ac , and the horizontal axis represents the reference operating point of the DC voltage V _dc. The change width ΔV _{dc from} is taken. The right figure of FIG. 3 is an operating characteristic diagram of the AC power generation system 101. The vertical axis represents the change width ΔV _ac from the reference operating point of the AC voltage V _ac , and the horizontal axis represents the output power PG from the reference operating point. The change width ΔPG is taken. By giving each of the AC / DC power converter 103 and the AC power generation system 101 the operating characteristics shown here in advance, each device operates autonomously according to the defined operating characteristics during the second protection control. It becomes possible to do. In FIG. 3, the case where the AC voltage V _ac , the DC voltage V _dc , and the power PG are all 1.0 [au] is illustrated as a reference operating point, but as long as the gist of the present invention is not deviated, the operating conditions may be changed. It can also be set to any reference operating point.

As shown in FIG. 2 (c), when the DC voltage V _dc reaches 1.1 [au] at time T2 and then the DC voltage V _dc further rises, according to the operation characteristic diagram of the left figure of FIG. The AC / DC power converter 103 raises the AC voltage _Vac by a predetermined amount.

Explaining this with reference to the left figure of FIG. 3, when the change width ΔV _dc increases by 0.1 [au] (when the DC voltage V _dc increases to 1.1 [au]), the AC / DC power converter 103 , As shown in the operation characteristics of the left figure of FIG. 3, the change width ΔV _ac is increased by 0.1 [au] (the AC voltage V _ac is increased to 1.1 [au]).

Further, as shown in the right figure of FIG. 3, when the change width ΔV _ac increases by 0.1 [au], each AC power generation system 101 reduces the power PG generated by each to 0 according to the operation characteristic diagram of the right figure of FIG. . Reduce by 2 [au]. Then, as each power PG decreases, the input power PG1 which is the sum of them also decreases by a predetermined amount. Since this second protection control is repeated while the DC voltage V _dc exceeds 1.1 [au], the input power PG1 gradually decreases, the difference between the input power PG1 and the output power PG2 approaches 0, and finally. The DC voltage V _dc is constant at the operation equilibrium point where the input power PG1 = the output power PG2.

As described above, if the input power PG1 and the output power PG2 do not match even with the first protection control, the DC voltage _Vdc can be kept constant by performing the second protection control. , It is possible to avoid the shutdown of the DC power generation system 101.

The above is the operation continuation control in the first embodiment, and when the power transmission capacity to the power system 105 is restored, the first protection control and the second protection control are stopped and returned to the state before the time T0. Each device in the DC power transmission system 100 may be controlled.

In Example 1, as shown in FIG. 3, the operating characteristics of the AC power generation system 101 were determined based on the AC voltage _Vac of the AC bus 102 as the second protection control, but the AC voltage V Instead of _ac , the determination may be made based on the voltage at the connection point between the AC power generation system 101 and the AC transmission line A111.

Further, in the first embodiment, the first protection control is performed and then the second protection control is performed, but in a form in which the first protection control and the second protection control are performed at the same time. There may be. In this case, when calculating the operation command value of the AC power generation system 101 in the first protection control, the first protection control and the second protection control can be calculated by taking into consideration the operation characteristic diagram of FIG. It is possible to avoid interference.

Next, the DC power transmission system 200 of the second embodiment will be described with reference to FIG. The DC power transmission system 200 of the present embodiment is obtained by connecting the power absorber 401 to the AC bus 102 of the first embodiment, and the other configurations are the same as those of FIG. 1, so duplicate description will be omitted.

In the first embodiment, the power generated by the AC power generation system 101 is reduced to continue the operation of the DC power transmission system 100 when the DC voltage _Vdc rises. However, in the second embodiment, the power absorption device 401 generates AC power. The input power PG1 from the system 101 is absorbed, and the operation of the DC transmission system 200 is continued when the DC voltage _Vdc rises. Hereinafter, the details of the operation continuation control when the DC voltage rises due to the decrease in the power transmission capacity to the power system 105 in the second embodiment will be described.

In the first embodiment, the operation command value was sent from the power generation system group control device 106 to the AC power generation system 101 in the first protection control, but in the second embodiment, the operation command value is transmitted to the AC power generation system 101. Instead, by transmitting the absorbed power command value to the power absorbing device 401 and controlling the amount of absorbed power in the power absorbing device 401, the same effect as the first protection control in the first embodiment can be obtained.

Further, regarding the second protection control, by providing the power absorbing device 401 with the same characteristics as the operation characteristics on the right side of FIG. 3 instead of the AC power generation system 101, it is equivalent to the second protection control in the first embodiment. The effect can be obtained.

From the above, even when the power absorbing device 401 is provided as in the second embodiment, the same effect as that of the first embodiment can be obtained.

In FIG. 4, the power absorbing device 401 was connected to only one place of the AC bus 102, but it was distributed and connected to each AC power generation system 101, and a plurality of storage batteries were connected by the power generation system group control device 106. It may be in a form of centralized control.

Next, the DC power transmission system 300 of the third embodiment will be described with reference to FIG. The DC power transmission system 300 of the present embodiment is provided with a system protection control device 501 that integrates these functions in place of the power generation system group control device 106 and the DC power transmission protection control device 107 of the first embodiment. Since the configurations other than the above are the same as those in FIG. 1, duplicate description will be omitted.

In the third embodiment, as compared with the first embodiment, the responsiveness of the protection control can be further improved by reducing the communication delay between the power generation system group control device 106 and the DC power transmission protection control device 107. That is, in the first embodiment, in the first protection control, the DC transmission protection control device 107 transmits the accident occurrence flag Flg and the power command value PG1 _ref , and the power generation system group control device 106 that receives them transmits the AC power generation system 101. However, in the third embodiment, the accident occurrence flag Flg and the power command value PG1 _ref are calculated in the system protection control device 501, and the operation command value of the power generation system 101 is calculated. , Communication delay can be reduced, and the same effect as in the first embodiment can be obtained more quickly.

In the third embodiment as well, similarly to FIG. 3 of the first embodiment, the operating characteristics of the AC power generation system 101 are determined based on the AC voltage _Vac of the AC bus 102 as the second protection control, but the AC voltage V Instead of _ac , the determination may be made based on the voltage at the connection point between the AC power generation system 101 and the AC transmission line A111.

Further, in the third embodiment, as in the first embodiment, the first protection control is performed and then the second protection control is performed, but the first protection control and the second protection control are performed. May be performed at the same time.

In this case, when calculating the operation command value of the AC power generation system 101 in the first protection control, the first protection control and the second protection control can be calculated by taking into consideration the operation characteristic diagram of FIG. It is possible to avoid interference.

Further, also in the third embodiment, similarly to the second embodiment, the power absorbing device 401 may be configured to be connected to the AC bus 102 or the AC power generation system 101.

Next, the DC power transmission system 400 of the fourth embodiment will be described with reference to FIG.

In the DC transmission system of Examples 1 to 3, the AC power generated by the AC power generation system 101 such as the wind power generation system is converted into DC by using the AC / DC power conversion device 103 and transmitted, and then again. The DC transmission system 400 of the fourth embodiment converts the DC power generated by the DC power generation system 601 such as a solar power generation system into DC / DC, although the DC power is converted into an alternating current and transmitted to the power system 105. The power conversion device 603 (DC-DC power conversion) boosts the voltage before transmitting the voltage, and the DC / AC power conversion device 104 converts DC to AC again and transmits the power to the power system 105. It will be described that even when the first and second protection controls are applied to the DC power transmission system 400, the same effects as those of the first to third embodiments can be obtained.

FIG. 6 is a system conceptual diagram of the DC transmission system 400 of the fourth embodiment, in which the AC power generation system 101 of FIG. 1 replaces the DC power generation system 601 and the AC bus 102 replaces the DC bus 602, and the AC / DC power converter 103. Replaced the DC / DC power converter 603, the AC transmission line A111 replaced the DC transmission line A604, the AC voltage detector 108 replaced the DC voltage detector 605, and the AC transmission line B112 replaced the DC transmission line B606. Is.

In the first protection control of the first embodiment, the generated power of the AC power generation system 101 is controlled based on the time change rate dV _dc of the DC transmission line 113, but even in the configuration of the present embodiment, the same first protection control is performed. The protection control of 1 can prevent the operation of the DC power generation system 601 from being stopped. Further, in the second protection control of the first embodiment, the generated power of the AC power generation system 101 is controlled based on the magnitude of the DC power _Vdc , but even in the configuration of the present embodiment, the equivalent second protection control is performed. It is possible to prevent the operation of the DC power generation system 601 from being stopped by the protection control of.

Regarding the second protection control, in FIG. 3 of the first embodiment, as a characteristic of the AC power generation system 101, the generated power can be controlled based on the AC voltage _Vac of the AC bus 102. In No. 4, as a characteristic of the DC power generation system 601, the generated power can be controlled based on the DC voltage V _dc2 of the DC bus 602 instead of the AC voltage V _ac , thereby _achieving the same effect as in the first embodiment. Obtainable.

Therefore, in Example 4, the same effect as in Example 1 can be obtained by carrying out the same protection control as in Example 1.

In the fourth embodiment, the operating characteristics of the DC power generation system 601 are determined based on the DC voltage V _dc2 of the DC bus 602 as the second protection control according to FIG. 3 of the first embodiment, but the DC voltage V _dc2 Alternatively, the determination may be made based on the voltage at the connection point between the DC power generation system 601 and the DC transmission line A604.

Further, in the fourth embodiment, similarly to the first embodiment, the first protection control is performed and then the second protection control is performed, but the first protection control and the second protection control are performed. May be duplicated.

In this case, when calculating the operation command value of the DC power generation system 601 in the first protection control, the first protection control and the second protection control are calculated by taking the operation characteristic diagram of FIG. 3 into consideration. It is possible to avoid interference.

Further, also in the fourth embodiment, similarly to the second embodiment, the power absorbing device 401 may be configured to be connected to the DC bus 602 or the DC power generation system 601. Further, also in the fourth embodiment, similarly to the third embodiment, the system protection control device 501 that integrates the functions of the power generation system group control device 106 and the DC power transmission protection control device 107 is used to suppress the signal delay between the two. It may be configured to be used.

100, 200, 300, 400 DC transmission system 101 AC power generation system 102 AC bus 103 AC / DC power conversion device 104 DC / AC power conversion device 105 Power system 106 Power generation system group control device 107 DC transmission protection control device 108 AC voltage detection Device 109 Power detector 110 DC voltage detector 111 AC transmission line A
112 AC transmission line B
113 DC transmission line 114 AC transmission line C
401 Power absorber 501 System protection control device 601 DC power generation system 602 DC bus 603 DC / DC power converter 604 DC transmission line A
605 DC voltage detector 606 DC transmission line B
Flg Accident occurrence flag V _ac AC voltage V _dc , V _dc2 DC voltage dV _dc Time change rate dV _dcth threshold PG1 Input power PG1 _ref Power command value PG2 Output power T0, T1, T2 Time

Claims (11)

A power generation system that generates electricity and
The first power conversion device that converts the input power from the power generation system into DC power,
A DC / AC power converter that converts DC power input from the first power converter into AC power, and
A DC transmission line connecting the first power conversion device and the DC / AC power conversion device,
A DC voltage detector that detects the DC voltage of the DC transmission line, and
A control device that controls the power generation system based on the output of the DC voltage detection device, and
It is a DC power transmission system equipped with
The control device executes the first protection control when the time change rate of the DC voltage detected by the DC voltage detection device exceeds the first threshold value.
A DC transmission system characterized in that a second protection control is executed when the DC voltage detected by the DC voltage detection device exceeds a second threshold value. In the DC power transmission system according to claim 1,
The power generation system is an AC power generation system.
The first power conversion device is an AC / DC power conversion device that converts AC power input from the AC power generation system into DC power.
The first protection control is a control for suppressing the AC power generated by the AC power generation system.
The second protection control is a DC power transmission system characterized in that it is a control for increasing an AC voltage generated by the AC power generation system. In the DC power transmission system according to claim 1,
The power generation system is a DC power generation system.
The first power conversion device is a DC / DC power conversion device that converts DC power input from the DC power generation system into DC power.
The first protection control is a control for suppressing the DC power generated by the DC power generation system.
The second protection control is a DC power transmission system characterized in that it is a control for increasing a DC voltage generated by the DC power generation system. The DC power transmission system according to any one of claims 1 to 3.
The control device is
A protective device that generates a power command value for controlling the output of the first power conversion device based on the DC voltage of the DC transmission line.
A power generation system group control device that calculates an operation command value that controls each of the plurality of power generation systems based on the power command value, and a power generation system group control device.
A DC power transmission system characterized by consisting of. In the DC power transmission system according to any one of claims 1 to 4.
A DC power transmission system characterized in that the second protection control is started after the first protection control is started. In the DC power transmission system according to any one of claims 1 to 4.
A DC power transmission system characterized by simultaneously executing the first protection control and the second protection control. In the DC power transmission system according to claim 4,
The protection device detects the DC voltage on the output side of the first power conversion device, and determines the voltage command of the power generation system based on the predetermined operating characteristics of the DC voltage and the transmission end voltage. A DC power transmission system featuring. In the DC power transmission system according to claim 4,
The power generation system is a DC power transmission system characterized in that the generated power of the power generation system is controlled based on a predetermined voltage on the input side of the first power conversion device and operating characteristics of the generated power. In the DC power transmission system according to any one of claims 1 to 8.
A DC power transmission system characterized in that a power absorbing device is connected to the input side of the first power conversion device. In the DC power transmission system according to any one of claims 1 to 8.
The first power conversion device or the DC / AC power conversion device is a DC transmission system characterized in that it is a self-excited power conversion device configured by using a self-extinguishing element. A control device that controls a power generation system used in a DC power transmission system.
The DC power transmission system
A power generation system that generates electricity and
The first power conversion device that converts the input power from the power generation system into DC power,
A DC / AC power converter that converts DC power input from the first power converter into AC power, and
A DC transmission line connecting the first power conversion device and the DC / AC power conversion device,
A DC voltage detector that detects the DC voltage of the DC transmission line, and
A control device that controls the power generation system based on the output of the DC voltage detection device, and
Consists of
When the time change rate of the DC voltage detected by the DC voltage detection device exceeds the first threshold value, the first protection control is executed.
A control device characterized in that a second protection control is executed when the DC voltage detected by the DC voltage detection device exceeds a second threshold value.

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