JPH11289670A - Two-pole dc power transmission system - Google Patents
Two-pole dc power transmission systemInfo
- Publication number
- JPH11289670A JPH11289670A JP10091590A JP9159098A JPH11289670A JP H11289670 A JPH11289670 A JP H11289670A JP 10091590 A JP10091590 A JP 10091590A JP 9159098 A JP9159098 A JP 9159098A JP H11289670 A JPH11289670 A JP H11289670A
- Authority
- JP
- Japan
- Prior art keywords
- return line
- line
- return
- ground fault
- power supply
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Landscapes
- Power Conversion In General (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Protection Of Static Devices (AREA)
- Supply And Distribution Of Alternating Current (AREA)
- Direct Current Feeding And Distribution (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、双極直流送電系統
に係り、特に並列運用される複数の帰線を有する双極直
流線路において、地絡事故を起こした帰線を判別するた
めに検出用交流電流を供給する交流電源を備えた双極直
流送電系統に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bipolar DC power transmission system, and more particularly, to a bipolar AC line having a plurality of return lines operated in parallel to detect a return line having a ground fault. The present invention relates to a bipolar DC power transmission system including an AC power supply for supplying current.
【０００２】[0002]
【従来の技術】直流送電系統は、直流線路の両端に交流
系統に連係される交直変換器を接続して形成され、直流
線路を介して２つの交流系統間で電力を送受する。そし
て、２系統の直流送電系統を正負２極に分け、各系統の
直流線路の中性点側の帰線を共通に接続して運用される
双極直流送電系統が知られている。この双極直流送電系
統の場合、運用上の観点から、帰線をそれぞれ個別に設
け、双極運用するときは複数の帰線の両端を開閉器によ
り共通接続し、単極運用するときは複数の帰線の両端を
開閉器により切り離すようにしている。2. Description of the Related Art A DC transmission system is formed by connecting AC / DC converters linked to an AC system to both ends of a DC line, and transmits and receives power between the two AC systems via the DC line. There is known a bipolar DC transmission system operated by dividing the two DC transmission systems into two positive and negative poles, and connecting the return lines on the neutral point side of the DC lines of each system in common. In the case of this bipolar DC transmission system, from the viewpoint of operation, return lines are individually provided, and when performing bipolar operation, both ends of a plurality of return lines are commonly connected by switches, and when performing unipolar operation, a plurality of return lines are provided. Both ends of the wire are separated by switches.
【０００３】このような双極直流送電系統の各系統の送
電電力がバランスしていると、帰線には電流が流れな
い。そのため、帰線に地絡事故が発生しても地絡電流が
流れないので検出することができない。そこで、従来、
各系統の帰線の一端を接地し、帰線の他端に地絡検出用
の交流電源を接続して、帰線に交流電流を常時流してお
き、それぞれの帰線に流れる交流電流の変化を地絡検出
リレーにより検出して、地絡を検出するようにしてい
る。If the transmission power of each system of such a bipolar DC transmission system is balanced, no current flows on the return line. For this reason, even if a ground fault occurs on the return line, the ground fault current does not flow and cannot be detected. So, conventionally,
One end of the return line of each system is grounded, and the other end of the return line is connected to an AC power supply for ground fault detection. Is detected by a ground fault detection relay to detect a ground fault.
【０００４】[0004]
【発明が解決しようとする課題】しかし、双極運用のと
きと単極運用のときでは、地絡検出用の交流電源からみ
たインピーダンスが異なるので、地絡検出リレーに流れ
る交流電流が変化してしまい、適正に地絡を検出するこ
とができない。However, the impedance seen from the AC power supply for detecting a ground fault differs between the bipolar operation and the unipolar operation, so that the AC current flowing through the ground detection relay changes. , The ground fault cannot be detected properly.
【０００５】そこで、双極直流送電系統の運用状態に合
わせて地絡検出用の交流電源の電圧を調整することによ
り、地絡検出リレーに流れる電流を一定に調整する必要
がある。Therefore, it is necessary to adjust the current flowing through the ground fault detection relay to a constant value by adjusting the voltage of the AC power supply for ground fault detection in accordance with the operation state of the bipolar DC transmission system.
【０００６】従来は、運用状態を運転員が判断し、これ
に基づいて地絡検出用の交流電源の電圧を手動で切り替
え、地絡検出リレーに流れる電流を一定に調整している
ことから、切り替えに要する時間が長くなり、しかも誤
操作の可能性があることから、操作性が悪いという問題
がある。Conventionally, the operator judges the operation state, manually switches the voltage of the AC power supply for ground fault detection based on this, and adjusts the current flowing through the ground fault detection relay to a constant value. There is a problem that operability is poor because the time required for switching becomes longer and there is a possibility of erroneous operation.
【０００７】本発明が解決しようとする課題は、上記問
題を解決すること、すなわち、双極直流送電系統の運用
形態に合わせて自動的に地絡検出用の交流電圧を調整可
能にすることにある。The problem to be solved by the present invention is to solve the above problem, that is, to make it possible to automatically adjust the AC voltage for ground fault detection in accordance with the operation mode of the bipolar DC power transmission system. .
【０００８】[0008]
【課題を解決するための手段】本発明は、交流系統に連
係される交直変換器を両端に備えてなる少なくとも２組
の直流送電系統を、正負の２極に分けて中性点側の帰線
の両端を開閉器を介して共通に接続し、前記開閉器を開
閉して２組の前記送電系統を双極運用と単極運用とに切
り替え可能に形成し、前記各帰線の一端を接地し、他端
に地絡検出用の交流電源を接続し、前記各帰線に流れる
交流電流に基づいて地絡を検出する地絡検出リレーを設
けてなる双極直流送電系統において、前記開閉器の開閉
状態に基づいて前記各直流送電系統の運用状態を判断し
て前記交流電源の出力電圧を調整する制御手段を備える
ことにより、課題を解決するものである。SUMMARY OF THE INVENTION The present invention divides at least two sets of DC transmission systems having AC / DC converters at both ends, which are linked to an AC system, into two positive and negative poles and returns the DC power to the neutral point. Both ends of the line are connected in common through a switch, and the switch is opened and closed to form two sets of the power transmission system so as to be switchable between bipolar operation and monopolar operation, and one end of each return line is grounded. The other end is connected to an AC power supply for ground fault detection, and in a bipolar DC power transmission system including a ground fault detection relay for detecting a ground fault based on the AC current flowing through each return line, the switch of the switch An object of the present invention is to solve the problem by providing control means for judging an operation state of each of the DC power transmission systems based on an open / close state and adjusting an output voltage of the AC power supply.
【０００９】すなわち、双極直流送電系統において、２
極の直流線路の帰線をそれぞれ単独に設けて、双極運用
又は単極運用を選択可能にする場合、少なくとも２極の
帰線の両端を開閉器（遮断容量が必要な場合は、遮断
器）を介して接続する。したがって、それらの開閉器又
は遮断器が全て閉状態にあれば、双極運用である。That is, in the bipolar DC transmission system, 2
In the case where the return of the DC line of the pole is provided independently and the bipolar operation or the single-pole operation can be selected, both ends of at least the return of the two poles are switched (breakers if a breaking capacity is required). Connect through. Therefore, if all of those switches or circuit breakers are in the closed state, the operation is bipolar.
【００１０】また、２極の帰線の接地端と接地極との間
に、それぞれ開閉器を設ける場合は、それらの開閉器の
開閉状態に応じて、両者が閉のときは双極運用の可能性
があり、いずれか一方が閉で他方が開のときは開の方の
極が停止している単極運用の状態にある。さらに、それ
ぞれの帰線の両端に開閉器を設けて、帰線を直流線路か
ら切り離せるようにした場合は、いずれかの帰線の両端
の開閉器が開であれば、その極の直流線路は不使用状態
にある。したがって、２極の直流線路の帰線の両端を接
続可能にする開閉器の開閉状態により、あるいはこれに
加えて２極の直流線路の帰線に設けられた開閉器の開閉
状態により、双極直流送電系統の運用状態を判断できる
ことになる。When switches are provided between the grounding end of the two-pole return line and the grounding pole, bipolar operation is possible when both switches are closed according to the open / closed state of the switches. When one of them is closed and the other is open, it is in the state of unipolar operation in which the open pole is stopped. Furthermore, if switches are provided at both ends of each return line so that the return line can be separated from the DC line, if the switches at both ends of either return line are open, the DC line Is not in use. Therefore, depending on the open / closed state of the switch that allows connection of both ends of the return line of the two-pole DC line, or in addition to this, the open / closed state of the switch provided on the return line of the two-pole DC line, The operation state of the transmission system can be determined.
【００１１】そこで、少なくとも帰線の両端を共通に接
続可能にする開閉器の開閉状態を検出することにより、
双極運用と単極運用を自動的に判断できるから、その判
断に合わせて交流電源の出力電圧を調整することによ
り、双極直流送電系統の運用形態に合わせて自動的に地
絡検出用の交流電圧を調整することができる。Therefore, by detecting the open / closed state of a switch that enables at least both ends of the return line to be commonly connected,
Bipolar operation and unipolar operation can be automatically determined, so by adjusting the output voltage of the AC power supply according to the determination, the AC voltage for ground fault detection can be automatically adjusted according to the operation mode of the bipolar DC transmission system. Can be adjusted.
【００１２】この場合において、制御手段は、各帰線に
流れる交流電流をほぼ設定値に保持するように交流電源
の出力電圧を調整することが好ましい。これによれば、
地絡検出の判定に係る設定値を厳しく設定できるから、
検出精度を高くすることができる。In this case, it is preferable that the control means adjusts the output voltage of the AC power supply so that the AC current flowing through each return line is maintained at a substantially set value. According to this,
Since the set value for the determination of ground fault detection can be set strictly,
Detection accuracy can be increased.
【００１３】[0013]
【発明の実施の形態】以下、本発明の実施の形態につい
て、図面を用いて説明する。図１に、本発明に係る双極
直流送電系統の一実施形態の構成図を示す。同図におい
て、双極直流送電系統は、２つの直流送電系統Ａ、Ｂと
を有して形成されている。直流送電系統Ａは、直流送電
線路の両端に交直変換器１Ａ，１Ｂと交直変換器２Ａ，
２Ｂとが接続されている。交直変換器１Ａ，１Ｂと交直
変換器２Ａ，２Ｂは、それぞれ交流系統４０，４１に接
続されている。それらの交直変換器１Ａ，１Ｂ，２Ａ，
２Ｂは、それぞれ交流を直流に、又は直流を交流に変換
する機能を有しており、サイリスタなどの半導体スイッ
チを用いて形成されている。直流送電系統Ａの直流線路
は、本線５と帰線６とからなる。本線５の一端は開閉器
５１と直流リアクトル９とを介して交直変換器１Ａの正
極に接続され、他端は開閉器５２と直流リアクトル１０
とを介して交直変換器２Ａの負極に接続されている。帰
線６の両端は、それぞれ開閉器５３を介して交直変換器
１Ｂの負極と、開閉器５４を介して交直変換器２Ｂの正
極とに接続されている。一方の直流送電系統Ｂは、直流
送電系統Ａと同様に、交直変換器３Ａ，３Ｂ，４Ａ，４
Ｂと、帰線７と本線８からなる直流線路を有して形成さ
れている。ただし、交直変換器３Ａの正極側に接続され
た線路を帰線７とし、交直変換器３Ｂの負極側に接続さ
れた線路を本線８としている点が相違している。この本
線８に、直流送電系統Ａと同様に、開閉器５７、直流リ
アクトル１１と開閉器５８、直流リアクトル１２が接続
されている。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of an embodiment of a bipolar DC power transmission system according to the present invention. In the figure, the bipolar DC transmission system is formed to have two DC transmission systems A and B. The DC transmission system A includes AC / DC converters 1A, 1B and AC / DC converters 2A,
2B is connected. The AC / DC converters 1A and 1B and the AC / DC converters 2A and 2B are connected to AC systems 40 and 41, respectively. The AC-DC converters 1A, 1B, 2A,
2B has a function of converting AC to DC or DC to AC, respectively, and is formed using a semiconductor switch such as a thyristor. The DC line of the DC transmission system A includes a main line 5 and a return line 6. One end of the main line 5 is connected to the positive electrode of the AC / DC converter 1A via a switch 51 and a DC reactor 9, and the other end is connected to a switch 52 and a DC reactor 10A.
To the negative electrode of the AC / DC converter 2A. Both ends of the return line 6 are connected to a negative electrode of the AC / DC converter 1B via a switch 53 and a positive electrode of the AC / DC converter 2B via a switch 54, respectively. One DC transmission system B, like the DC transmission system A, has AC / DC converters 3A, 3B, 4A, 4
B, and a DC line composed of a return line 7 and a main line 8. However, the difference is that the line connected to the positive electrode side of the AC / DC converter 3A is the return line 7 and the line connected to the negative electrode side of the AC / DC converter 3B is the main line 8. The switch 57, the DC reactor 11, the switch 58, and the DC reactor 12 are connected to the main line 8, similarly to the DC power transmission system A.
【００１４】そして、帰線６の交直変換器１Ｂ側の一端
は、開閉器１４を介して接地されている。同様に、帰線
７の交直変換器３Ａ側の一端は、開閉器１５を介して接
地されている。帰線６と帰線７の他端は、開閉器５４と
遮断器１３と開閉器５６とを介して共通接続可能にされ
ている。One end of the return line 6 on the AC / DC converter 1B side is grounded via a switch 14. Similarly, one end of the return line 7 on the AC / DC converter 3A side is grounded via a switch 15. The other ends of the return line 6 and the return line 7 can be commonly connected via a switch 54, a circuit breaker 13, and a switch 56.
【００１５】帰線６、７の反接地側の端部に、地絡検出
用の交流電源装置２５と交流電源装置３５がそれぞれ接
続されている。交流電源装置２５、３５は、それぞれ、
交流電源２０と、絶縁変圧器２１と、絶縁変圧器２１の
２次側に並列接続されたコンデンサ２２とを有して形成
されている。コンデンサ２２の一端は接地され、他端は
コンデンサ２３と開閉器２４、５４（又は開閉器３４、
５６）とを介して帰線６（又は、７）に接続されてい
る。なお、交流電源装置２５と交流電源装置３５は、双
極運用のときは、いずれか一方のみを使用し、他方は予
備装置とする。単極運用のときは両方を使用する。その
切り替えは、開閉器２４，３４で行う。An AC power supply 25 and an AC power supply 35 for detecting a ground fault are connected to the ends of the return lines 6 and 7 on the side opposite to the ground. The AC power supplies 25 and 35 are respectively
It is formed to include an AC power supply 20, an insulating transformer 21, and a capacitor 22 connected in parallel to the secondary side of the insulating transformer 21. One end of the capacitor 22 is grounded, and the other end is connected to the capacitor 23 and the switches 24, 54 (or the switch 34,
56) to the return line 6 (or 7). In the case of bipolar operation, only one of the AC power supply device 25 and the AC power supply device 35 is used, and the other is a standby device. For monopolar operation, use both. The switching is performed by switches 24 and 34.
【００１６】また、帰線６、７の接地端から離れた端部
に地絡検出リレー１６，１７が設けられている。地絡検
出リレー１６、１７は、それぞれ電流変成器１，１９８
により検出される帰線６，７の交流電流が、予め設定さ
れた判定基準値以上の時に、帰線６，７の地絡事故を検
出するようになっている。Further, ground fault detection relays 16 and 17 are provided at ends of the return lines 6 and 7 which are remote from the grounding ends. The ground fault detection relays 16 and 17 are connected to the current transformers 1 and 198, respectively.
When the AC current of the return lines 6 and 7 detected by the above is equal to or greater than a predetermined reference value, a ground fault accident of the return lines 6 and 7 is detected.
【００１７】次に、本発明の特徴部の構成について説明
する。帰線保護装置８０には、線路開閉器５３、５４、
５５、５６と、２極分離用の線路開閉器１４、１５と、
２極分離用の遮断器１３の開閉状態を示す状態信号が入
力されている。帰線保護装置８０は、入力される状態信
号に基づいて、双極直流送電系統の運用状態、特に帰線
６，７の運用状態を次の条件により判断する。Next, the configuration of the characteristic portion of the present invention will be described. The return line protection device 80 includes line switches 53, 54,
55, 56, line switches 14, 15 for 2-pole separation,
A state signal indicating the open / close state of the circuit breaker 13 for bipolar separation is input. The return line protection device 80 determines the operation state of the bipolar DC transmission system, particularly the operation state of the return lines 6 and 7 based on the input state signal under the following conditions.
【００１８】（１）線路開閉器５３、５４、５５、５６
と、２極分離用の線路開閉器１４、１５と、２極分離用
の遮断器１３の全てが閉状態にあるときは、系統Ａ、Ｂ
の両方の帰線６，７が運用状態にあることを判断する。 （２）２極分離用の線路開閉器１４、１５のうち、線路
開閉器１４のみが開状態にあるときは、系統Ａが停止し
ている単極運用状態にあると判断し、線路開閉器１５の
みが開状態にあるときは、系統Ｂが停止している単極運
用状態にあると判断しする。線路開閉器１４、１５の両
方が開状態にあるときは、系統Ａ、Ｂともに停止してい
ると判断する。 （３）線路開閉器５３、５４が開状態にあるときは、帰
線６が不使用の状態にあり、また、線路開閉器５５、５
６が開状態にあるときは、帰線７が不使用の状態にある
と判断する。(1) Line switches 53, 54, 55, 56
When all of the line switches 14, 15 for separating the two poles and the circuit breaker 13 for separating the two poles are in the closed state, the systems A, B
It is determined that both return lines 6 and 7 are in operation. (2) When only the line switch 14 of the two-pole separating line switches 14 and 15 is in an open state, it is determined that the system A is in a single-pole operation state in which the system A is stopped, and the line switch is determined. When only 15 is in the open state, it is determined that the system B is in the monopolar operation state in which the system B is stopped. When both the track switches 14 and 15 are in the open state, it is determined that both the systems A and B are stopped. (3) When the line switches 53 and 54 are in the open state, the return line 6 is in an unused state.
When 6 is in the open state, it is determined that the return line 7 is in an unused state.
【００１９】そして、帰線保護装置８０は、上記判断の
結果に基づいて、交流電源２０又は３０に出力電圧を変
更する指令を送り、地絡検出用の交流電流を運用状態に
合わせて予め設定されている設定電流を帰線に流すよう
になっている。The return line protection device 80 sends a command to change the output voltage to the AC power supply 20 or 30 based on the result of the determination, and sets the AC current for ground fault detection in advance according to the operation state. The set current is set to flow to the return line.
【００２０】このように構成される実施の形態の動作を
次に説明する。直流送電系統Ａは、例えば、交流系統４
０から供給される交流電力を交直変換器１Ａ，１Ｂによ
り直流電力に変換し、直流線路である本線５と帰線６を
介して交直変換器２Ａ，２Ｂに送電する。交直変換器２
Ａ，２Ｂは、送電された直流電力を交流電力に変換して
交流系統４１に供給する。なお、交流系統４１から交流
系統４０に電力を逆方向に送電することも可能である。
同様に、直流送電系統Ｂも交流系統４０と交流系統４１
の間で電力を送受する。The operation of the embodiment constructed as described above will be described below. The DC transmission system A is, for example, an AC system 4
AC power supplied from 0 is converted into DC power by AC / DC converters 1A and 1B, and transmitted to AC / DC converters 2A and 2B via a main line 5 and a return line 6 which are DC lines. AC / DC converter 2
A and 2B convert the transmitted DC power into AC power and supply it to AC system 41. In addition, it is also possible to transmit electric power from the AC system 41 to the AC system 40 in the reverse direction.
Similarly, the DC transmission system B also includes an AC system 40 and an AC system 41
Send and receive power between
【００２１】ここで、直流送電系統Ａ，Ｂの運用につい
て簡単に説明する。まず、遮断器１３と線路開閉器１
４，１５、５３〜５６を閉状態にすることにより、双極
運転になる。この場合、帰線６と帰線７に流れ込む電流
が互いに逆向きで、互いに打ち消しあうから、帰線６と
帰線７に流れる電流が低減され、送電ロスを少なくする
ことができる。特に、双極運転時に直流送電系統Ａ、Ｂ
の送電電力量を等しくすると、帰線６と帰線７に流れる
電流を零にすることができ、このような運用を双極バラ
ンス運転と称している。一方、遮断器１３を開放状態に
して運転すると、直流送電系統Ａ、Ｂをそれぞれ単独で
運転又は停止することができる。停止する場合は、該当
する系統の線路開閉器１４，１５を開にする。Here, the operation of the DC transmission systems A and B will be briefly described. First, the circuit breaker 13 and the line switch 1
Closing 4, 15, 53-56 results in bipolar operation. In this case, since the currents flowing into the return lines 6 and 7 are opposite to each other and cancel each other, the current flowing through the return lines 6 and 7 is reduced, and power transmission loss can be reduced. In particular, DC transmission systems A and B during bipolar operation
If the amount of transmitted power is equal, the current flowing through the return line 6 and the return line 7 can be reduced to zero, and such operation is called bipolar balance operation. On the other hand, when the circuit breaker 13 is operated in the open state, the DC power transmission systems A and B can be operated or stopped independently. When stopping, the line switches 14, 15 of the corresponding system are opened.
【００２２】ここで、双極バランス運転時における地絡
保護の動作について説明する。まず、双極運転時は、開
閉器２４、３４のいずれか一方を開放して、地絡検出用
の交流電源装置２５、３５のいずれか一方を帰線６，帰
線７に接続し、他方を予備とする。ここでは、交流電源
装置２５が帰線６に接続されているものとして説明す
る。交流電源装置２５のコンデンサ２２は、絶縁変圧器
２１を介して交流電源２０によって充電される。このコ
ンデンサ２２の交流電圧は、コンデンサ２３と開閉器５
４とを介して帰線６に印加され、さらに遮断器１３と開
閉器５６とを介して帰線７に印加される。これにより、
コンデンサ２２→コンデンサ２３→開閉器２４→開閉器
５４、５６→帰線６，７→開閉器５３、５５→開閉器１
４、１５→接地→コンデンサ２２のルートで交流電流が
流れる。ここで、例えば、帰線６のＦ１点で地絡事故が
発生すると、帰線６を含む接地回路ではコンデンサ２２
→コンデンサ２３→開閉器２４→開閉器５４→帰線６の
Ｆ１点→接地→コンデンサ２２のルートで交流電流が流
れる。一方、帰線７の接地回路には、上述した地絡事故
が生じていない正常時の交流電流が流れる。図２に、上
述の接地回路の等価回路を示す。抵抗６１とリアクタン
ス６２は帰線６のインピーダンスであり、抵抗７１とリ
アクタンス７２は帰線７のインピーダンスである。Here, the operation of ground fault protection during bipolar balance operation will be described. First, at the time of bipolar operation, one of the switches 24, 34 is opened, and one of the AC power supply devices 25, 35 for detecting a ground fault is connected to the return line 6, the return line 7, and the other is connected. Make a spare. Here, description will be given assuming that AC power supply device 25 is connected to return line 6. The capacitor 22 of the AC power supply 25 is charged by the AC power supply 20 via the insulating transformer 21. The AC voltage of the capacitor 22 is connected to the capacitor 23 and the switch 5.
4 to the return line 6, and further to the return line 7 via the circuit breaker 13 and the switch 56. This allows
Capacitor 22 → Capacitor 23 → Switch 24 → Switches 54 and 56 → Return 6,7 → Switches 53 and 55 → Switch 1
An alternating current flows through the route of 4, 15 → ground → capacitor 22. Here, for example, if a ground fault occurs at the F1 point of the return line 6, in the ground circuit including the return line 6, the capacitor 22
AC current flows through the route of the capacitor 23 → switch 24 → switch 54 → return line F1 point → ground → capacitor 22. On the other hand, in the ground circuit of the return line 7, an alternating current in a normal state where the above-mentioned ground fault has not occurred flows. FIG. 2 shows an equivalent circuit of the above-described ground circuit. The resistance 61 and the reactance 62 are the impedance of the return line 6, and the resistance 71 and the reactance 72 are the impedance of the return line 7.
【００２３】正常時に各帰線の接地回路に流れる交流電
流は、リアクタンス６２，７２によって定まる。帰線６
のＦ１点で地絡事故が発生した場合、帰線６の接地回路
に流れる交流電流は帰線６のリアクタンス６２の一部分
をバイパスするので、地絡事故が発生していない場合よ
り大きな交流電流になる。これにより、地絡検出リレー
１６は、帰線６に流れる交流電流が判定基準値以上であ
ることを検出して、帰線６に地絡事故が発生したことを
検出する。一方、地絡検出リレー１７は、正常時と同じ
交流電流が流れているので動作しないから、帰線を選別
して地絡検出を行うことができる。The alternating current flowing in the ground circuit of each return line in a normal state is determined by reactances 62 and 72. Return 6
When a ground fault occurs at the point F1 of the above, since the AC current flowing through the ground circuit of the return line 6 bypasses a part of the reactance 62 of the return line 6, the AC current becomes larger than when no ground fault occurs. Become. Thus, the ground fault detection relay 16 detects that the AC current flowing through the return line 6 is equal to or greater than the determination reference value, and detects that a ground fault accident has occurred on the return line 6. On the other hand, the ground fault detection relay 17 does not operate because the same alternating current flows as in the normal state, so that the ground fault can be detected by selecting the return line.
【００２４】ここで、帰線６，７に流す地絡検出用の交
流電流はできるだけ低い値が好ましい。また、地絡検出
リレー１６，１７に設定される判定基準値は、地絡点位
置の違いに対応するために厳しく設定される。したがっ
て、各帰線に流す地絡検出用の交流電流は一定値に保持
することが重要である。ところが、双極運用の状態から
単極運用若しくは１極停止に移行するとき、逆に、単極
運用若しくは１極停止から双極運用に移行するとき、交
流電源装置２５から見た負荷インピーダンスが大きく変
わるから、各帰線の交流電流を一定値に保持するには、
交流電源２０の出力電圧を調整する必要がある。Here, it is preferable that the AC current for detecting a ground fault flowing through the return lines 6 and 7 is as low as possible. The criterion values set in the ground fault detection relays 16 and 17 are set strictly in order to cope with the difference in the ground fault point position. Therefore, it is important that the AC current for ground fault detection flowing in each return line is kept at a constant value. However, when the state shifts from the bipolar operation to the unipolar operation or the unipolar stop, and conversely, when the state shifts from the unipolar operation or the unipolar stop to the bipolar operation, the load impedance viewed from the AC power supply device 25 greatly changes. , To keep the AC current of each return line constant
It is necessary to adjust the output voltage of the AC power supply 20.
【００２５】そこで、本実施の形態では、開閉器１４、
１５、５３、５４、５５、５６と遮断器１３の開閉状態
の状態信号に基づいて、前述した条件に従って帰線保護
装置８０により帰線の運用状態を判断する。この判断に
従って、各帰線に供給される電流を一定に保持するよう
に交流電源２０を制御する。例えば、図２において、帰
線が１本だけで運用されていた場合の交流電源装置側か
ら見たインピーダンスは、Ｒｃ＋ｊＸｃとなり、このと
きの運用電圧は、Ｖ１＝Ｉ（Ｒｃ＋ｊＸｃ）となる。一
方、帰線が２本で運用されていた場合の交流電源装置側
から見たインピーダンスは、（Ｒｃ＋ｊＸｃ）／２とな
り、帰線に流す電流Ｉを一定にするとこのときの運用電
圧は、Ｖ２＝Ｉ×（Ｒｃ＋ｊＸｃ）／２＝Ｉ（Ｒｃ＋ｊ
Ｘｃ）／２＝Ｖ１／２とする必要がある。Therefore, in this embodiment, the switch 14,
Based on the state signals of the open / closed state of the circuit breaker 13, 15, 53, 54, 55, 56, the return line protection device 80 determines the return line operation state in accordance with the above-described conditions. According to this determination, the AC power supply 20 is controlled so as to keep the current supplied to each return line constant. For example, in FIG. 2, the impedance viewed from the AC power supply device side when only one return line is used is Rc + jXc, and the operation voltage at this time is V1 = I (Rc + jXc). On the other hand, the impedance viewed from the AC power supply device side when two return lines are operated is (Rc + jXc) / 2, and when the current I flowing through the return line is constant, the operating voltage at this time is V2 = I × (Rc + jXc) / 2 = I (Rc + j
Xc) / 2 = V1 / 2.
【００２６】このように、帰線保護装置８０は、帰線の
運用状態によって、交流電源２０又は３０を制御して、
各帰線に流す電流を運用状態によらず一定に制御する。
これにより、帰線６、７の運用本数にかかわらず、運用
される帰線に流れる電流値が変わらないので、判定基準
値に基づいて地絡の有無を検出する地絡検出リレー１
６、１７の動作を適切にすることができる。As described above, the flyback protection device 80 controls the AC power supply 20 or 30 depending on the operation state of the flyback,
The current flowing through each return line is controlled to be constant regardless of the operation state.
As a result, the current value flowing through the operated return lines does not change irrespective of the number of operation of the return lines 6 and 7, so that the ground fault detection relay 1 that detects the presence or absence of a ground fault based on the determination reference value is provided.
Operations 6 and 17 can be made appropriate.
【００２７】また、帰線保護装置８０は、地絡検出リレ
ー１６が動作した場合には，帰線６が地絡したことを、
地絡検出リレー１７が動作した場合には、帰線７が地絡
したことを判断し、地絡故障した直流送電系統を切り離
して停止し、健全極による運用を可能とする。When the ground fault detection relay 16 operates, the return line protection device 80 detects that the return line 6 has a ground fault.
When the ground fault detection relay 17 is operated, it is determined that the return line 7 is grounded, the DC transmission system having the ground fault is separated and stopped, and operation with a healthy pole is enabled.
【００２８】[0028]
【発明の効果】以上説明したように、本発明によれば、
複数の帰線を有する双極直流送電系統において、双極直
流送電系統の運用形態に合わせて自動的に地絡検出用の
交流電圧を調整可能にすることができる。As described above, according to the present invention,
In a bipolar DC transmission system having a plurality of return lines, the AC voltage for ground fault detection can be automatically adjusted in accordance with the operation mode of the bipolar DC transmission system.
【図１】本発明に係る双極直流送電系統の一実施形態の
構成図である。FIG. 1 is a configuration diagram of an embodiment of a bipolar DC power transmission system according to the present invention.
【図２】図１の実施形態に係る地絡回路の等価回路であ
る。FIG. 2 is an equivalent circuit of the ground fault circuit according to the embodiment of FIG.
１，２，３，４ 交直変換器 ５，８ 本線 ６，７ 帰線 ９，１０，１１，１２ 直流リアクトル １３ 遮断器 １４，１５ 線路開閉器 ５３，５４，５５，５６ 線路開閉器 １６，１７ 地絡検出リレー ２０，３０ 交流電源 ２５，３５ 交流電源装置 ４０，４１ 交流系統 ８０ 帰線保護装置 1,2,3,4 AC / DC converter 5,8 Main line 6,7 Return line 9,10,11,12 DC reactor 13 Circuit breaker 14,15 Line switch 53,54,55,56 Line switch 16,17 Ground fault detection relay 20, 30 AC power supply 25, 35 AC power supply 40, 41 AC system 80 Return protection device
Claims (2)
に備えてなる少なくとも２組の直流送電系統を、正負の
２極に分けて中性点側の帰線の両端を開閉器を介して共
通に接続し、前記開閉器を開閉して２組の前記直流送電
系統を双極運用と単極運用とに切り替え可能に形成し、
前記各帰線の一端を接地し、他端に地絡検出用の交流電
源を接続し、前記各帰線に流れる交流電流に基づいて地
絡を検出する地絡検出リレーを設け、前記開閉器の開閉
状態に基づいて前記各直流送電系統の運用状態を判断し
て前記交流電源の出力電圧を調整する制御手段を備えて
なる双極直流送電系統。1. At least two sets of DC power transmission systems having AC / DC converters at both ends linked to an AC system are divided into positive and negative poles, and both ends of a return line on the neutral point side are connected via switches. Connected in common, the switch is opened and closed to form two sets of the DC transmission system switchable between bipolar operation and monopolar operation,
One end of each return line is grounded, the other end is connected to an AC power supply for detecting a ground fault, and a ground fault detection relay for detecting a ground fault based on an AC current flowing through each return line is provided. A bipolar DC power transmission system comprising control means for judging an operation state of each of the DC power transmission systems based on the open / close state of the AC power supply and adjusting an output voltage of the AC power supply.
流電流をほぼ設定値に保持するように前記出力電圧を調
整することを特徴とする請求項１に記載の双極直流送電
系統。2. The bipolar DC power transmission system according to claim 1, wherein said control means adjusts said output voltage so as to keep an alternating current flowing through each of said return lines at substantially a set value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10091590A JPH11289670A (en) | 1998-04-03 | 1998-04-03 | Two-pole dc power transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10091590A JPH11289670A (en) | 1998-04-03 | 1998-04-03 | Two-pole dc power transmission system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11289670A true JPH11289670A (en) | 1999-10-19 |
Family
ID=14030776
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10091590A Pending JPH11289670A (en) | 1998-04-03 | 1998-04-03 | Two-pole dc power transmission system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11289670A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008145578A2 (en) * | 2007-05-25 | 2008-12-04 | Siemens Aktiengesellschaft | Device for high-voltage direct current transmission |
| CN103558488A (en) * | 2013-08-16 | 2014-02-05 | 国家电网公司 | High impedance grounding fault detection device based on transient state travelling waves |
| CN111830431A (en) * | 2020-06-23 | 2020-10-27 | 中国电力科学研究院有限公司 | Method and system for judging fault of true bipolar flexible direct current transmission system |
| JP6910579B1 (en) * | 2020-11-11 | 2021-07-28 | 三菱電機株式会社 | Power conversion system and its control device |
| EP3965243A1 (en) * | 2020-09-04 | 2022-03-09 | General Electric Technology GmbH | Improvements in or relating to bipole power transmission schemes |
| JP2022077493A (en) * | 2020-11-11 | 2022-05-23 | 三菱電機株式会社 | Power conversion system and control device thereof |
-
1998
- 1998-04-03 JP JP10091590A patent/JPH11289670A/en active Pending
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008145578A2 (en) * | 2007-05-25 | 2008-12-04 | Siemens Aktiengesellschaft | Device for high-voltage direct current transmission |
| WO2008145578A3 (en) * | 2007-05-25 | 2009-01-29 | Siemens Ag | Device for high-voltage direct current transmission |
| RU2468486C2 (en) * | 2007-05-25 | 2012-11-27 | Сименс Акциенгезелльшафт | High-voltage direct current transfer device |
| CN103558488A (en) * | 2013-08-16 | 2014-02-05 | 国家电网公司 | High impedance grounding fault detection device based on transient state travelling waves |
| CN111830431A (en) * | 2020-06-23 | 2020-10-27 | 中国电力科学研究院有限公司 | Method and system for judging fault of true bipolar flexible direct current transmission system |
| CN111830431B (en) * | 2020-06-23 | 2023-07-04 | 中国电力科学研究院有限公司 | Method and system for carrying out fault discrimination on true bipolar flexible direct current transmission system |
| EP3965243A1 (en) * | 2020-09-04 | 2022-03-09 | General Electric Technology GmbH | Improvements in or relating to bipole power transmission schemes |
| WO2022049188A1 (en) * | 2020-09-04 | 2022-03-10 | General Electric Technology Gmbh | Improvements in or relating to bipole power transmission schemes |
| JP6910579B1 (en) * | 2020-11-11 | 2021-07-28 | 三菱電機株式会社 | Power conversion system and its control device |
| WO2022102027A1 (en) * | 2020-11-11 | 2022-05-19 | 三菱電機株式会社 | Power conversion system and control device for same |
| JP2022077493A (en) * | 2020-11-11 | 2022-05-23 | 三菱電機株式会社 | Power conversion system and control device thereof |
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