JPS61137081A - Failed point positioning apparatus of dc transmitting system - Google Patents
Failed point positioning apparatus of dc transmitting systemInfo
- Publication number
- JPS61137081A JPS61137081A JP59259626A JP25962684A JPS61137081A JP S61137081 A JPS61137081 A JP S61137081A JP 59259626 A JP59259626 A JP 59259626A JP 25962684 A JP25962684 A JP 25962684A JP S61137081 A JPS61137081 A JP S61137081A
- Authority
- JP
- Japan
- Prior art keywords
- current
- accident
- power transmission
- transmission line
- current value
- 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.)
- Granted
Links
Landscapes
- Emergency Protection Circuit Devices (AREA)
- Direct Current Feeding And Distribution (AREA)
- Locating Faults (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
この発明は直流送電線の短絡事故（地絡事故２）の発生
点の位置を送電端側で検出する直流送電系の故障点評定
装置に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a failure point evaluation device for a DC power transmission system that detects the position of the point of occurrence of a short circuit accident (earth fault accident 2) in a DC power transmission line at the power transmission end side.
従来の技術
故障点評定装置としては、マーレーループ法やバーレー
ループ法のよう−こ、線路を含むブリッジ形の回路を構
成し、その平衡条件から故障点までの距離を求めるもの
が良く知られている。この種の装置ではブリッジ形測定
回路を平衡させるような測定操作が必要で、直流送電系
において、その電流値の変化から一時にかつ直接的に故
障点を評定することはできなかった。Conventional technical failure point evaluation devices include the Murray loop method, the Burley loop method, and the well-known devices that construct a bridge-type circuit including a line and calculate the distance to the failure point from its equilibrium condition. There is. This type of device requires measurement operations such as balancing the bridge-type measurement circuit, and in a DC power transmission system, it is not possible to immediately and directly determine the fault point from changes in the current value.
発明が解決しようとする間鴎点
近年、一定時間Δｔでサンプリングされた電流データを
用いて故障点を即座に評定する手段が考えられるように
なって来た。この評定手段は第７図に示すように故障点
が送電端の至近部であると特性曲線Ａのように゛１流変
化八 が大きくなることを利用して故障点の評定を良好
に得ることになる。この例として％願昭５９−１９０９
０号がある。しかし、故障点が送電端から遠方にあると
第７図の特性曲線Ｂに示すように電流変化１Ｂが小さい
。このため、一定時間Δｔの変化に対応した電流変化Ｉ
Ｂ が１示のように小さくなるため、評定誤差が生じ
てくる問題点がある。そこで、この評定誤差を解消する
ために、サンプリング時間へｔを長くすると特性ｌ１１
１線人の場合の′＃Ｉｔ流変化流口化範囲的でなくなる
（飽和部分）ため、至近端故障時の評定誤差が生じてし
まう問題点がある。Problems to be Solved by the Invention In recent years, means for immediately evaluating failure points using current data sampled at a certain period of time Δt has come to be considered. As shown in Fig. 7, this evaluation method utilizes the fact that when the failure point is close to the transmission end, the change in current flow increases as shown in characteristic curve A, to obtain a good evaluation of the failure point. become. As an example of this,
There is No. 0. However, if the failure point is far from the power transmission end, the current change 1B is small as shown by characteristic curve B in FIG. Therefore, the current change I corresponding to the change in constant time Δt
Since B becomes small as shown in 1, there is a problem that a rating error occurs. Therefore, in order to eliminate this evaluation error, if t is increased to the sampling time, the characteristic l11
Since the '#It flow change in the case of a one-line person is no longer consistent with the flow range (saturated portion), there is a problem in that an evaluation error occurs in the case of a near-end failure.
問題点を解決するための手段及び作用
この発明は直流送′蝋線の送゛ＷＬ端側でその電流値を
所定周期で連続的ｌこサンプリングする手段と、サンプ
リングされた上記電流値の変化を常時監視して上記送電
線の短絡事故の発生を噴出する手段と、事故発生が検出
されたとき、その事故により増加するＶｔａ値の電ｆｔ
変化に対するサンプリング時刻を送電端側の電圧値およ
び上記送電線の巣位長さ当りのインピーダンスにより第
１次線形近似された微分解析演算によって上記故障点ま
での上記送電線の長さを算出する手段とから構成され。Means and Operation for Solving the Problems This invention provides means for continuously sampling the current value at a predetermined period on the sending WL end side of a DC feeding wire, and detecting changes in the sampled current value. Means for constantly monitoring and alerting the occurrence of a short-circuit accident in the power transmission line, and when the occurrence of an accident is detected, the electric ft of Vta value increases due to the accident.
Means for calculating the length of the power transmission line up to the failure point by a differential analysis calculation in which the sampling time for the change is first-order linearly approximated by the voltage value on the power transmission end side and the impedance per focal length of the power transmission line. It is composed of.
前記電流変化に要する時間を測定することにより遠方で
の故障で電流変化が緩やかなときでも正確に故障点を評
定できる。By measuring the time required for the current change, the failure point can be accurately evaluated even when the current change is gradual due to a failure in a distant place.
実施例
以下図面を参照してこの発明の一実施例を説明する前ｌ
こ、第４図及び第５図により故障点評定の原理について
説明する。EXAMPLE Before explaining one embodiment of the present invention with reference to the drawings,
The principle of failure point evaluation will be explained with reference to FIGS. 4 and 5.
第４図は直流送礪系の等価回路図で、１は厘流砿源、２
は送゛嘱線、Ｒは線路抵抗％Ｌは線路インピーダンス、
Ｒｆは故障点抵抗、Ｘは故障”点である。Figure 4 is an equivalent circuit diagram of a DC feed system, where 1 is a hot current source, 2
is the transmission line, R is the line resistance %L is the line impedance,
Rf is the failure point resistance, and X is the failure point.
なお、Ｒｏ＆′ｉ直流区源直流区部１抗で、以下では無
視する。上記回路において、送電端電圧をＶとすると、
その電圧ｖ ＆ｉ線路抵抗Ｒおよび線路インピーダンス
Ｌを介して故障点Ｘに印加され、゛電流１は故障点抵抗
Ｒｆに流れる。Note that Ro&'i is the DC section source and DC section 1 resistor, and will be ignored below. In the above circuit, if the sending end voltage is V,
The voltage v &i is applied to the fault point X via the line resistance R and line impedance L, and the current 1 flows to the fault point resistance Rf.
次に、事故が発生した場合、任意の′ｖｔ流［ｉにおけ
る送゛一端電圧ｖ （ｔ）は次の微分方程式で表わすこ
とができる。Next, when an accident occurs, the voltage at the sending end v (t) at any 'vt flow [i] can be expressed by the following differential equation.
ｖ （ｔｌ＝ Ｌ ” ＋ Ｒｔ （ｔｌ −
−−（１）コｒ「
第５図は上記事故が発生したときの′１流、電圧特性図
であり、この発明では所定周期で電流１を連続的にサン
プリングしている。そのサンプリング時点を’ｔ ｔｆ
ｌ ｔ、・・・・・・と表わし、対応するサンプリン
グ電流値をｉｌｌ １１ｔ ｉｓ・・・・・とし、相前
後する２点の電流サンプル値の差ｉ、 −１，、ｉ、−
ｉ、 甲・・を電流変化Δ１フ、Δ１１ ・・・とす
る。この電流変化Δ１ｎを常時監視し、Δ１ｎが予め設
定した整定値Ｋを越えたとき、送電線２に事故（地絡）
が発生したものと判定する。その後、以下に述べる原理
で故障点を評定する。v (tl=L ” + Rt (tl −
--(1) Figure 5 is a current and voltage characteristic diagram when the above-mentioned accident occurs.In this invention, current 1 is continuously sampled at a predetermined period. 't tf
It is expressed as l t,..., the corresponding sampling current value is ill 11t is..., and the difference between the current sample values at two successive points is i, -1,, i, -.
Let i, A... be current changes Δ1f, Δ11... This current change Δ1n is constantly monitored, and when Δ1n exceeds a preset setting value K, an accident (ground fault) occurs in the power transmission line 2.
It is determined that this has occurred. After that, the failure point is evaluated using the principle described below.
上述の谷サンプル時点”１９ ｔｌ、 ｔ、・・・での
電圧Ｖをそれぞれｖ、 Ｉ Ｖｆｆ＋ ｖｌ・・・・・
と表わすと、（］）式の微分方程式ｔこついて次のよう
な第１次の房形近似が成立する。The voltage V at the above-mentioned valley sample time ``19 tl, t, ... is respectively v, I Vff+ vl...
When expressed as , the following first-order tufted approximation holds true when the differential equation t in equation ( ]) is satisfied.
（２）式と′（３）式を腑算すると（４）式になる。Equation (4) is obtained by calculating equation (2) and equation (3).
同様にして、任意の゛鴫Ｒ値Ｌａ、Ｌｍ のときのｖ
Ｉ＋７．は次式になる。Similarly, v at arbitrary R values La and Lm
I+7. becomes the following formula.
”１２ ＋ ’ｆ＠ ”ｔ、−Ｉ；、（’２−１３）＋
Ｒ（１１＋１８） ” 川（５）次に（４）式ｘ （ｔ
ｚ＋ｔｓ）−（ｓ）式Ｘ（１，＋１．）は（６）式のよ
うになる。``12 + 'f@''t, -I;, ('2-13)+
R(11+18) ” River (5) then (4) equation x (t
z+ts)-(s) Equation X(1,+1.) becomes as shown in Equation (6).
（Ｖ＋＋ｖ！Ｘ：Ｌｔ＋１ｇ ） −ｔｌ−ｔｌ （１
＋−１ｄ（１＊”ｉｇ ）”（”１＋ｖりＤ＋＋１１）
−ｔ、−ｔ、（ｉｔ−１ｍ）（１＋”ｉｍ）・・・・・
・・・・（６）
ｔｌ −１１＝”２− ｔｌ ＊ ｔ、 −１１＝’４
〜１．と考えると（６）式は次式のようｌζなる。(V++v!X:Lt+1g) -tl-tl (1
+-1d(1*"ig)"("1+vriD++11)
-t, -t, (it-1m) (1+"im)...
...(6) tl -11="2- tl * t, -11='4
~1. Considering this, equation (6) becomes lζ as shown in the following equation.
１、−１．＝ｉ、−１．から ｉｔ ＝（ｉ＋ ”ｉｍ
）／ ２ ・旧・・（８）送電端から距離Ｘの点で事故
の場合、送電端から見た線路抵抗Ｒおよびインダクタン
スＬは次のようになる。1, -1. =i, -1. From it = (i+ ”im
)/2 - Old... (8) In the case of an accident at a point at distance X from the power transmission end, the line resistance R and inductance L seen from the power transmission end are as follows.
Ｒｍ ｒｘ ＋ Ｒｆ、、、 、、、 、、、 （ｇ）
Ｌミム １９０１１０９０．１υｕＩ式を（７）
に代入して整理すると
ここで、直流送電系では直流電源１はナイリスタなどに
よる定電正整Ｓ丸器によって構成されるため、短絡覇故
が発生しても第５図に示した゛−圧Ｖはほとんど変化し
ないので、Ｖｌｅ”ｌ＊Ｖ１をそれぞれＶとするとα１
式は次式のようになる。Rm rx + Rf, , , , , , (g)
L Mim 19011090.1υuI formula (7)
Here, in a DC power transmission system, the DC power supply 1 is composed of a constant current adjustment S-circle using a Nyristor, etc., so even if a short circuit fault occurs, the voltage V shown in Figure 5 does not change much, so if Vle"l*V1 is V, α1
The formula is as follows.
前記（８）式をα３式に代入すると次式ｌこなる。Substituting the above equation (8) into the α3 equation yields the following equation.
０３式より１．、ｉ、の′ＩＩｔ流サンプすング他での
演算式は
Ｉ式から短絡φ故時に事故電流が予め設定された電流１
［１１及び１．になる時刻１．．１．を知ること番こよ
り、故障点の評定演算ができる。これにより故障点での
距離Ｘを算出できる。From formula 03, 1. , i, 'IIt flow sampling etc. The calculation formula for the IIt flow sampling etc. is based on the formula I. When a short circuit φ occurs, the fault current is the preset current 1.
[11 and 1. The time when 1. ．． 1. By knowing this, you can calculate the rating of the failure point. This allows the distance X at the failure point to be calculated.
なお、実際ｌζ使用するデータは高速でナンプリングさ
れている電流データで任意に設定された電流埴’ａ ＋
’ｂ （第６図に示す）より大となる電流データｉｎ
ｔ！（ｔ＋≧ｉａ 、 ｉ、≧ｉｂ ）と、その時刻
ｔＩｓｔ、により演算される。In addition, the data actually used is current data that is numbered at high speed, and is arbitrarily set as current data.
'b (shown in Figure 6)
T! (t+≧ia, i,≧ib) and the time tIst.
次に、この発明に係る故障点評定装置の具体的な実施例
について述べる。゛
第１図において、交流電源１１が定電圧整流５ｉ１２で
［流に変換される。変換された直流電圧は送電ｉ１！２
に供給される。送電線２の送電端側には抵抗１３ａ、１
３１）で分圧された電圧Ｖが４８磯アンプ１４を介して
４／Ｔ）変！ｌＩ器１５に供給される。また、送′一端
側には直流しゃ断器１６と直流電流検出器１７とが設け
られている。電流検出ａ１７は例えばホール素子などを
用いたもので、送を線２上の直流電流の大きさを検出す
る。検出された電流１゛はめ変換器１５に供給される。Next, a specific embodiment of the failure point evaluation device according to the present invention will be described. In FIG. 1, an AC power source 11 is converted into a current by a constant voltage rectifier 5i12. The converted DC voltage is transmitted to i1!2
supplied to Resistors 13a and 1 are connected to the power transmission end side of the power transmission line 2.
The voltage V divided by 31) changes to 4/T) through the 48 Iso amplifier 14! It is supplied to the II unit 15. Furthermore, a DC breaker 16 and a DC current detector 17 are provided at one end of the feeder. The current detection a17 uses, for example, a Hall element, and detects the magnitude of the direct current on the feed line 2. The detected current 1 is supplied to the inset transducer 15.
ｂ勺ｆ換・された信号はコンピュータに伝送される。こ
の間の信号伝送は光ファイバを用いて光信号で行うと良
い。 ゛上記ゴンピエータは（ｊＰｏ １Ｂ
、 ＲＯＭ・ｉ９ｔ １ｍＭ２０゜出力部２１．入
力部２２ 、 ＤＭＡ ２３および整定部２４からな
り、Ａ／′Ｄ賀挨ｉ１５の信号はＶ夏Ａ ２３に入力さ
れる。The converted signal is transmitted to a computer. Signal transmission during this period is preferably performed using optical fibers.゛The above gompiator is (jPo 1B
, ROM・i9t 1mM20° output section 21. It consists of an input section 22, a DMA 23, and a setting section 24, and the signal of the A/'D signal i15 is input to the V summer A23.
ＲＯＭ １９には例えば送電線２０単位インダクタンス
ｊをメモリしておく。ＲＡＭ ２０ ｊこは電流値等が
メそりされる。また、出力部２１から動作出力が送出さ
れる。The ROM 19 stores, for example, the inductance j of 20 power transmission lines. In the RAM 20, current values and the like are memorized. In addition, the output section 21 outputs the operation output.
次に上記実施例の動作を第２図のフロチャートを用いて
述べる。最初のステップＳ１で、ＤＭＭ２Ｂ５介してチ
ンプリング時点１ｎのサンプリング電流値（データ）１
ｎを取り込み、 ＲＡＭ ２０の所定エリアに一時記憶
する。次のステップＳ、で、今回のサンプリングデータ
１ｎと前回のサンプリングデータ１ｎ−３との差Δ１ｎ
を演算処理する。この演算処理後、ステップＳｌ＃こて
Δ１ｎと整定値にとの大小比較判断を行い、事故発生の
監視を行う。すなわち、へ−ｒｈ＜Ｋのときは正常と判
断し、ステップ８＋＊８ｔｓＳｓヲ繰返す。Next, the operation of the above embodiment will be described using the flowchart shown in FIG. In the first step S1, the sampling current value (data) 1 at the chimpling time point 1n is
n is taken in and temporarily stored in a predetermined area of the RAM 20. In the next step S, the difference Δ1n between the current sampling data 1n and the previous sampling data 1n-3
Compute. After this arithmetic processing, a comparison is made between the iron Δ1n and the set value in step Sl#, and the occurrence of an accident is monitored. That is, when h-rh<K, it is determined to be normal, and step 8+*8tsSs is repeated.
前記ステップＳ、でΔ１ｎ≧Ｋ となったとき、事故が
発生したものと判断し、ステップＳ４に進む。When Δ1n≧K in step S, it is determined that an accident has occurred, and the process proceeds to step S4.
ステップＳ４では最新のサンプリングデータ１ｎと前回
のチンプリングデータ１ｎ−１の′電流変化に対する時
刻を得て、前記一式を演算する。このときＲＯＭ １９
からインダクタンスｊや゛這圧Ｖを読み出して０式の演
算を行う。ステップ日、では演算結果故障点までの距離
Ｘが算出される。この結果は出力部２１から動作出力と
して送出される。その後、最初のステップに戻り、同様
の処理を行う。In step S4, the time with respect to the current change of the latest sampling data 1n and the previous chimpling data 1n-1 is obtained, and the above-mentioned set is calculated. At this time, ROM 19
The inductance j and the creeping pressure V are read out from the equation 0 and calculated. On the step date, the distance X to the failure point is calculated as a result of the calculation. This result is sent out from the output section 21 as an operation output. After that, return to the first step and perform the same process.
第３図は故障点が送電端側に近い場合と遠い場合におけ
る電流の変化を示す特性図で、曲線ムが故障点が近いと
き１曲線Ｂ力Ｓ遠いときである。この第３図から電流変
化Δ１（１□−１１）に要する時間ｔム、 ｔＢを測定
すれば故障点評定が正確にできる。FIG. 3 is a characteristic diagram showing changes in current when the fault point is close to the power transmission end side and when it is far from the power transmission end side, where curve M is close to the fault point and curve B is far away. If the time tm and tB required for the current change Δ1 (1□-11) are measured from FIG. 3, the failure point can be accurately evaluated.
発明の効果
以上述べたように、この発明によれば、直流送電系に地
絡（短絡）事故が発生したとき、任意の′Ｑｃ流変比変
化する時間を測定することにより送電端から近い距離は
勿論、それから遠方の距離での故障点を正確に評定でき
る利点がある。Effects of the Invention As described above, according to the present invention, when a ground fault (short circuit) occurs in a DC power transmission system, by measuring the time for any Qc current ratio change, Of course, it has the advantage of being able to accurately assess failure points at long distances.
第１図はこの発−の一実施例を示す嘴成説明図、第２図
は（ｊＰＨの処理内容を示すフローチャート。
第３図は故障点が送電端側に近いときと遠いときの電流
変化を示す特性図、第４図はこの発明の詳細な説明する
ための［ｆｉ！ｍ系の等価回路図、第５図はｉ］ＩＲ送
電系送電路故障による電流・電圧の変化を示す特性図、
第６図は電流特性図、第７図は従来例を述べるための電
流特性図である。
１１・・・交流電源、１２・・・定電圧整訛器、１４・
・・絶縁アンプ、１５・・・シ勺変換器、ｔ６・・・し
ゃ断器、１７・・・電流検出器、１８・・・ａｙσ、１
９・・・ＲＯＭ、ｌυ・・ＲＡＭ、２１・・・出力部、
２２・・・入力部、２３・・・′ＤＭＡ、２４・・・整
定部。Fig. 1 is an explanatory diagram showing an example of this generator, Fig. 2 is a flowchart showing the processing contents of (jPH), and Fig. 3 shows current changes when the fault point is near and far from the power transmission end. FIG. 4 is an equivalent circuit diagram of the [fi!m system] for detailed explanation of this invention, and FIG. 5 is a characteristic diagram showing changes in current and voltage due to power transmission line failure in the IR power transmission system ,
FIG. 6 is a current characteristic diagram, and FIG. 7 is a current characteristic diagram for describing a conventional example. 11...AC power supply, 12...constant voltage regulator, 14.
・・Isolation amplifier, 15・・Shinori converter, t6・・・breaker, 17・・current detector, 18・・・ayσ, 1
9...ROM, lυ...RAM, 21...output section,
22... Input section, 23...'DMA, 24... Setting section.
Claims (1)
連続的にサンプリングする手段と、サンプリングされた
上記電流値の変化を常時監視して上記送電線の短絡事故
の発生を検出する手段と、事故発生が検出されたとき、
その事故により増加する電流値の電流変化に対するサン
プリング時刻を送電端側の電圧値および上記送電線の単
位長さ当りのインピーダンスにより第１次線形近似され
た微分解析演算によつて上記事故点までの上記送電線の
長さを算出する手段とを備えた直流送電系の故障点評定
装置。(1) A means for continuously sampling the current value at a predetermined period on the transmission end side of the DC transmission line, and constantly monitoring changes in the sampled current value to detect the occurrence of a short-circuit accident in the transmission line. means and when an accident occurrence is detected,
The sampling time for the current change in the current value that increases due to the fault is determined by the voltage value on the transmission end side and the impedance per unit length of the transmission line using a differential analysis calculation that is first-order linearly approximated. A failure point evaluation device for a DC power transmission system, comprising means for calculating the length of the power transmission line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59259626A JPH0812221B2 (en) | 1984-12-07 | 1984-12-07 | DC power transmission system fault location device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59259626A JPH0812221B2 (en) | 1984-12-07 | 1984-12-07 | DC power transmission system fault location device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61137081A true JPS61137081A (en) | 1986-06-24 |
| JPH0812221B2 JPH0812221B2 (en) | 1996-02-07 |
Family
ID=17336687
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59259626A Expired - Lifetime JPH0812221B2 (en) | 1984-12-07 | 1984-12-07 | DC power transmission system fault location device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0812221B2 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008149776A (en) * | 2006-12-14 | 2008-07-03 | Inoac Corp | Spoiler |
| JP2008149777A (en) * | 2006-12-14 | 2008-07-03 | Inoac Corp | Spoiler and its manufacturing method |
| JP2019191021A (en) * | 2018-04-26 | 2019-10-31 | 株式会社日立製作所 | Failure point location device, failure point location system, and method for locating failure point |
| CN112260252A (en) * | 2020-10-14 | 2021-01-22 | 云南电网有限责任公司文山供电局 | Protection method of low-voltage direct-current ring network system |
| WO2022219788A1 (en) * | 2021-04-15 | 2022-10-20 | 日本電信電話株式会社 | Dc power distribution system, control device, operation state determination method, and program |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5372144A (en) * | 1976-12-10 | 1978-06-27 | Hitachi Ltd | Standaedization device of trouble point |
| JPS58225362A (en) * | 1982-06-24 | 1983-12-27 | Toshiba Corp | Digital troubled point locating apparatus |
-
1984
- 1984-12-07 JP JP59259626A patent/JPH0812221B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5372144A (en) * | 1976-12-10 | 1978-06-27 | Hitachi Ltd | Standaedization device of trouble point |
| JPS58225362A (en) * | 1982-06-24 | 1983-12-27 | Toshiba Corp | Digital troubled point locating apparatus |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008149776A (en) * | 2006-12-14 | 2008-07-03 | Inoac Corp | Spoiler |
| JP2008149777A (en) * | 2006-12-14 | 2008-07-03 | Inoac Corp | Spoiler and its manufacturing method |
| JP2019191021A (en) * | 2018-04-26 | 2019-10-31 | 株式会社日立製作所 | Failure point location device, failure point location system, and method for locating failure point |
| CN112260252A (en) * | 2020-10-14 | 2021-01-22 | 云南电网有限责任公司文山供电局 | Protection method of low-voltage direct-current ring network system |
| WO2022219788A1 (en) * | 2021-04-15 | 2022-10-20 | 日本電信電話株式会社 | Dc power distribution system, control device, operation state determination method, and program |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0812221B2 (en) | 1996-02-07 |
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| Date | Code | Title | Description |
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| EXPY | Cancellation because of completion of term |