JPH0210650B2 - - Google Patents
Info
- Publication number
- JPH0210650B2 JPH0210650B2 JP7864682A JP7864682A JPH0210650B2 JP H0210650 B2 JPH0210650 B2 JP H0210650B2 JP 7864682 A JP7864682 A JP 7864682A JP 7864682 A JP7864682 A JP 7864682A JP H0210650 B2 JPH0210650 B2 JP H0210650B2
- Authority
- JP
- Japan
- Prior art keywords
- current
- phase
- line
- ground fault
- zero
- 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.)
- Expired
Links
- 238000004364 calculation method Methods 0.000 claims description 14
- 230000005540 biological transmission Effects 0.000 claims description 13
- 230000007935 neutral effect Effects 0.000 claims description 9
- 238000004088 simulation Methods 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims description 7
- 230000005611 electricity Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 4
- 238000000059 patterning Methods 0.000 description 3
- 230000009897 systematic effect Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Landscapes
- Emergency Protection Circuit Devices (AREA)
Description
本発明は、高抵抗接地系平行多回線の地絡保護
方式に係り、特に３端子系統に対して優れた方式
を提供するものである。
平行多回線系統、例えば２回線、４回線におい
て、系統構成によつては系統の各相間の相互イン
ダクタンスが不平衡となり負荷電流によつて回線
間を循環する誘導電流（以下循環電流と称する）
が発生する。特に、１回線停止、２回線停止や１
端子開放時で発生する循環電流は著しく、これは
１線地絡時に中性点抵抗器から供給される故障電
流に較べて無視できない。このため、循環電流の
零相分（以下零相循環電流と称する）で地絡保護
リレーが誤動作しないようリレータツプ値を上げ
ている。従つて、零相循環電流の増加に伴ない高
感度の保護ができないという問題がある。
平行４回線系統を地絡故障から保護する回線選
択継電方式に於いては、これまで前述の問題解決
のため、常時の零相電流を記憶しておき、故障時
の零相電流の変化分によつて故障回線の判別を行
う方法がある。ところが、この方式は原理上、故
障前後の零相電流の変化分で応動するために、相
手端近傍の内部故障で相手端が先行してしや断
（シリーストリツプ）した場合には、零相循環電
流が変化するので故障回線の判別が難かしい。こ
のために、２端子系統では故障発生後一定時間
（相手端先行しや断以前の時間）経過すると従来
の回線選択継電器に切り換えて故障回線の判別を
行う方式がとられている。３端子系統では、相手
端先行しや断を２回経験する３段階シリーストリ
ツプで故障が除去されるために上記の方式では充
分な効果が期待できない。
第１図は本発明を平行４回線３端子系統に適用
した場合を示すものである。１１〜１４は母線を
示し、２１〜２５は送電回線を示し、S1〜S6は電
気所を示す。２１〜２４はS1〜S2まで同一鉄塔に
併架されている。２１，２２は位置P1、P2より
分岐してS3まで平行２回線として構成される。２
３，２４は位置P3、P4より分岐してS4まで平行
２回線として構成される。さらに２３，２４は位
置P5、P6より分岐してS5，S6まで単独回線とし
て構成される。また、S1とS4は、単独回線２５で
連係される。G1〜G7は送電区間を示し、その鉄
塔装柱図が第２図に示される。この第２図でａ，
ｂ，ｃは相を示す。
上記の系統を系統シミユレーシヨンして零相循
環電流を計算した結果を第１表に示す。
The present invention relates to a ground fault protection system for parallel multi-line high resistance grounding systems, and particularly provides an excellent system for three-terminal systems. In a parallel multi-circuit system, for example, two lines or four lines, depending on the system configuration, the mutual inductance between each phase of the system may become unbalanced, causing an induced current (hereinafter referred to as circulating current) that circulates between lines due to load current.
occurs. In particular, 1 line outage, 2 line outage, 1 line outage,
The circulating current generated when the terminal is open is significant and cannot be ignored compared to the fault current supplied from the neutral point resistor during a one-line ground fault. For this reason, the relay tap value is increased so that the ground fault protection relay does not malfunction due to the zero-sequence portion of the circulating current (hereinafter referred to as zero-sequence circulating current). Therefore, there is a problem in that highly sensitive protection cannot be achieved as the zero-phase circulating current increases. In the line selective relay system that protects parallel four-line systems from ground faults, in order to solve the above-mentioned problem, the constant zero-sequence current is memorized and the change in zero-sequence current at the time of a fault is calculated. There is a method of determining a faulty line by However, in principle, this method responds to the change in zero-sequence current before and after a fault, so if the other end is first interrupted due to an internal fault near the other end (series strip), the zero-sequence circulation is interrupted. Since the current changes, it is difficult to identify the faulty line. For this reason, in a two-terminal system, a system is adopted in which the faulty line is determined by switching to a conventional line selection relay after a certain period of time (time before the other end precedes or breaks) after the failure occurs. In a three-terminal system, the above method cannot be expected to be sufficiently effective because faults are eliminated by a three-stage series strip in which the other end experiences leading and breaking twice. FIG. 1 shows the case where the present invention is applied to a parallel four-line three-terminal system. 11 to 14 indicate busbars, 21 to 25 indicate power transmission lines, and S 1 to S 6 indicate electric stations. 21 to 24 are installed together on the same steel tower from S 1 to S 2 . 21 and 22 are configured as two parallel lines branching from positions P 1 and P 2 to S 3 . 2
3 and 24 are configured as two parallel lines branching from positions P 3 and P 4 to S 4 . Furthermore, lines 23 and 24 branch from positions P 5 and P 6 and are configured as individual lines up to S 5 and S 6 . Further, S 1 and S 4 are linked through a single line 25. G 1 to G 7 indicate power transmission sections, and a diagram of the tower installation is shown in Figure 2. In this figure 2, a,
b and c indicate phases. Table 1 shows the results of calculating the zero-sequence circulating current by simulating the above system.
【表】
理論的には、循環電流はそれを誘導する負荷電
流に比例する。上記の通り系統シミユレーシヨン
結果もそれを示す。その性質を要約すると次の通
りとなる。
性質１ ａ、ｂ、ｃ相及び零相循環電流I〓ac，
I〓bc，I〓cc，I〓pcは、それを誘導する負荷電流に比
例する。
性質２ その比例定数は、平行４回線系統運用状
態、その電線配置及び負荷電流分布によつて定
まる。
性質３ 性質１、２より、次に定義する零相循環
電流Ipcと２つの相循環電流から正相分を除外
した量とのベクトル比は平行４回線系統運用状
態（その電線配置）及び負荷電流分布によつて
定まる。
第１図の系統構成図を系統シミユレーシヨンし
て得られた循環電流により定数K〓a、K〓b、K〓cを
求めた結果を第２表に示す。[Table] Theoretically, circulating current is proportional to the load current inducing it. As mentioned above, the systematic simulation results also show this. Its properties can be summarized as follows. Property 1 a, b, c phase and zero phase circulating current I〓ac,
I〓 bc , I〓 cc , I〓 pc are proportional to the load current that induces them. Property 2 The proportionality constant is determined by the operating status of the parallel 4-circuit system, its wire arrangement, and load current distribution. Property 3 From Properties 1 and 2, the vector ratio of the zero-sequence circulating current I pc defined below to the amount obtained by excluding the positive-sequence component from the two-phase circulating currents is determined by the operating state of the parallel four-circuit system (its wire arrangement) and the load. Determined by current distribution. Table 2 shows the results of determining the constants K〓a, K〓b, and K〓c from the circulating current obtained by performing a system simulation on the system configuration diagram shown in Fig. 1.
【表】
本発明は、上記性質(1)〜(3)に基づいてなされた
ものである。
ａ相に１線地絡故障が起きた場合に、送電線２
１と２２、または送電線２３と２４との健全相で
あるｂ相、Ｃ相差電流I〓bd，I〓cdには故障電流成分
は含まれず次のようになる。
I〓bd＝I〓bc＋I〓bL …(2)
I〓cd＝I〓cc＋I〓cL …(3)
但し、
I〓bL，I〓cL；送電線２１と２２、または送電線２３
と２４との差電流として生じるｂ相及び相負荷
電流（以下負荷電流と称す）。
I〓bc，I〓cc；送電線２１と２２、または送電線２３
と２４との間を循環する誘導によるｂ相及びｃ
相循環電流（以下循環電流と称す）。
差電流に負荷電流が含まれるのは分岐端負荷が
存在する場合は相手端先行しや断した場合であ
る。ａ相1φG（１線地絡）時に健全相の差電流に
含まれる負荷電流の影響を取り除くために、Ｃ相
差電流を120゜進めて、ｂ相差電流とのベクトル差
をとる。
I〓bd−aI〓cd＝I〓bc＋I〓bL−ａ（I〓cc＋I〓cL）
＝I〓bc−aI〓cc＋（I〓bL−aI〓cL） …(4)
但し、
ａ＝exp（ｊ２／３π）
負荷電流は、ほとんど正相成分のみから構成さ
れているので、(4)式の演算で負荷電流は消去され
る。
よつて、
I〓bd−aI〓cd＝I〓bc−aI〓cc …(5)
先に述べた定数K〓aすなわち零相循環電流I〓Ocと
ｂ相及びＣ相循環電流から正相分を除外した量と
の比率は、系統運用状態とその負荷電流分布が定
まれば一定値となるので、ａ相１線地絡時に於い
て次式に示す通り定数K〓aと健全相差電流から正
相分を除外した量とのベクトル積演算によつてａ
相地絡時の零相循環電流を演算することができ
る。(1)、(5)式から
I〓Oc(es)＝K〓a×（I〓bd−aI〓cd）
＝K〓a×（I〓bc−aI〓cc） …(6)
但し、I〓Oc(es)は零相循環電流の演算値。
一方、一般に高抵抗平行２回線の地絡保護継電
方式として使用されている回線選択継電方式は、
零相電圧E0を基準とした零相差電流I〓Od（当該平行
２回線の差電流の零相分）の方向及び大きさによ
つて故障回線を選択するものである。ところが平
行４回線等の併架系統においては、系統運用状態
によつて零相循環電流が発生し、１線地絡時の零
相差電流I〓Odは故障による中性点抵抗器電流成分I〓f
と零相循環電流I〓Ocとの合成値となり次の通りと
なる。
I〓Od＝I〓f＋I〓Oc …(7)
この零相循環電流は、地絡故障とは無関係であ
るために、従来形リレーでは零相循環電流によつ
て不正動作しないようにリレータツプ値を上げて
故障検出感度を低下させなければならない。
本発明では(7)式の零相差電流に含まれる零相循
環電流I〓Ocを、上記の方法で求めた零相循環電流
の演算値I〓Oc(es)を使つて次の通り打ち消す。
（補償する）
I〓Od(es)＝I〓cd−I〓Oc(es)
＝I〓f＋I〓Oc−I〓Oc(es) …(8)
演算値3I〓Oc(es)による補償が完全であれば、I〓Oc
＝
I〓Oc(es)となり(8)式の補償値3I〓Od(es)によつて正し
い中
性点抵抗器電流成分I〓fを得ることができる。
この補償値I〓Oc(es)及び零相電圧V〓Oを回線選択継
電器の入力電流、電圧とすることによつてリレー
タツプ値は零相循環電流の大きさに左右されるこ
となく高感度整定が可能となり従来形に比較して
地絡故障検出感度を飛躍的に向上させることがで
きる。ｂ相またはｃ相１線地絡時にも同様の考え
方により、２組の健全相差電流から正相分を除外
した量に対して(1)式の定数K〓aまたはK〓cを乗ずる
ことによつて零相循環電流を演算し、零相電流に
含まれる零相循環電流を補償することができる。
以下に示す零相循環電流の演算値の誤差（以下
演算誤差と称す）に対しては前記の定数K〓a、K〓b、
K〓cの値が大きく影響するのでその値の設定が重
要である。
ΔI〓Oc＝｜I〓Oc−I〓Oc(es)｜ …(9)
但し、
ΔI〓Oc；零相循環電流の演算算誤差。
｜ ｜；絶対値を示す。
ところが、定数K〓a、K〓b、K〓cは、第２表で示
した通り系統運用状態に応じて別個の値をとるた
めに、定数の設定は演算誤差をできるだけ小さく
するよう次のように行う。
継電器設置端子の各回線の電流を測定し１線地
絡によつて変化しない基準電圧に対するその有効
分の大小関係や電流なしの条件によつて数種のパ
タンに分類し、それぞれの個々のパタンに対して
該当する幾つかの系統運用ケースで生じる演算誤
差を最小化するような定数K〓set a、K〓set b、K〓set c
を、
あらかじめ当該系統のシミユレーシヨンで求めて
おく。
第１図の系統で回線２１，２２を保護する電気
所S2の回線選択地絡継電器に対して系統運用パタ
ンに区分けする条件とそれら個々のパターンに対
する最適定数K〓set a、K〓set b、K〓set cを大形計算機
で求
めた結果を第３表−(1)および第３表−(2)に示す。[Table] The present invention has been made based on the above properties (1) to (3). If a 1-wire ground fault occurs on phase a, the transmission line 2
The b-phase and C-phase difference currents I〓 bd , I〓 cd which are healthy phases between 1 and 22 or the transmission lines 23 and 24 do not include a fault current component and are as follows. I〓 bd ＝I〓 bc +I〓 bL …(2) I〓 cd ＝I〓 cc +I〓 cL …(3) However, I〓 bL , I〓 cL ; Transmission lines 21 and 22, or transmission line 23
b-phase and phase load current (hereinafter referred to as load current) generated as a difference current between and 24. I〓 bc , I〓 cc ; Transmission lines 21 and 22, or transmission line 23
b phase and c due to induction circulating between and 24
Phase circulating current (hereinafter referred to as circulating current). The load current is included in the difference current when a load at the branch end is present and when the other end is ahead or disconnected. In order to remove the influence of the load current included in the difference current of the healthy phase at the time of a-phase 1φG (one wire ground fault), advance the C-phase difference current by 120 degrees and take the vector difference with the b-phase difference current. I〓 bd −aI〓 cd =I〓 bc +I〓 bL −a(I〓 cc +I〓 cL ) =I〓 bc −aI〓 cc +(I〓 bL −aI〓 cL ) …(4) However, a= exp(j2/3π) Since the load current consists almost only of positive phase components, the load current is eliminated by the calculation of equation (4). Therefore, I〓 bd −aI〓 cd = I〓 bc −aI〓 cc …(5) The constant K〓a mentioned earlier, that is, the zero-sequence circulating current I〓 Oc and the positive phase component from the b-phase and C-phase circulating currents. The ratio to the amount excluding the amount will be a constant value once the system operation status and its load current distribution are determined, so at the time of a phase one wire ground fault, it can be calculated from the constant K〓a and the healthy phase difference current as shown in the following formula. By vector product operation with the quantity excluding the positive phase component, a
The zero-sequence circulating current at the time of a phase-to-ground fault can be calculated. From equations (1) and (5), I〓 Oc(es) = K〓 a × (I〓 bd −aI〓 cd ) = K〓 a × (I〓 bc −aI〓 cc ) …(6) However, I 〓 Oc(es) is the calculated value of zero-sequence circulating current. On the other hand, the line selection relay system, which is generally used as a ground fault protection relay system for two high-resistance parallel lines,
The faulty line is selected based on the direction and magnitude of the zero-sequence difference current I〓 Od (zero-sequence portion of the difference current between the two parallel lines) based on the zero-sequence voltage E0 . However, in parallel systems such as four parallel circuits, a zero-sequence circulating current occurs depending on the system operation status, and the zero-sequence difference current I〓 Od at the time of a one-line ground fault is the neutral point resistor current component I〓 due to a fault. f
The composite value of and the zero-sequence circulating current I〓Oc is as follows. I〓 Od ＝I〓 f ＋I〓 Oc …(7) Since this zero-sequence circulating current has nothing to do with ground faults, conventional relays set the relay tap value to prevent malfunction due to zero-sequence circulating current. The fault detection sensitivity must be reduced by increasing the In the present invention, the zero-sequence circulating current I〓 Oc included in the zero-sequence difference current in equation (7) is canceled as follows using the calculated value I〓 Oc(es) of the zero-sequence circulating current obtained by the above method. (Compensate) I〓 Od(es) = I〓 cd −I〓 Oc(es) = I〓 f +I〓 Oc −I〓 Oc(es) …(8) Calculated value 3I〓 Compensation by Oc(es) If complete, I〓 Oc
=
I〓 Oc(es) , and the correct neutral point resistor current component I〓 f can be obtained by the compensation value 3I〓 Od(es) of equation (8). By setting this compensation value I〓 Oc(es) and the zero-sequence voltage V〓 O as the input current and voltage of the line selection relay, the relay tap value can be set with high sensitivity without being affected by the magnitude of the zero-sequence circulating current. This makes it possible to dramatically improve ground fault detection sensitivity compared to conventional types. Using the same concept, when a one-wire ground fault occurs in phase B or phase C, the amount obtained by excluding the positive phase component from the two pairs of healthy phase difference currents is multiplied by the constant K〓 a or K〓 c in equation (1). Therefore, it is possible to calculate the zero-sequence circulating current and compensate for the zero-sequence circulating current included in the zero-sequence current. The following constants K〓 a , K〓 b ,
Since the value of K〓c has a large influence, setting that value is important. ΔI〓 Oc = ｜I〓 Oc −I〓 Oc(es) ｜ …(9) However, ΔI〓 Oc : Calculation error of zero-sequence circulating current. | |; Indicates absolute value. However, the constants K〓a, K〓b, and K〓c take different values depending on the system operation status as shown in Table 2, so the constants are set as follows to minimize the calculation error. Do it like this. The current in each line of the relay installation terminal is measured and classified into several patterns depending on the magnitude of the effective portion relative to the reference voltage that does not change due to a one-line ground fault and the no-current condition, and each individual pattern is Constants K〓 set a , K〓 set b , K〓 set c that minimize the calculation error that occurs in some grid operation cases corresponding to
of,
Determine this in advance by simulating the system in question. Conditions for dividing the line selection ground fault relay of electric station S 2 that protects lines 21 and 22 into system operation patterns in the system shown in Figure 1 and optimal constants K〓 set a , K〓 set b for each pattern , K〓 set c obtained using a large-scale computer are shown in Table 3-(1) and Table 3-(2).
【表】
. . . .
但し、ここでI２１、 I２２、 I２３、 I２４は
回線21、 22、 23、 24の有効電流を示す。
【table】 . . . .
However, here, I 21 , I 22 , I 23 , and I 24 indicate the effective currents of the lines 21, 22, 23, and 24.
【表】【table】
【表】【table】
【表】【table】
【表】
これらの最適定数に対して、第２表の負荷条件
で演算誤差を求めた結果、その最大値は、系統運
用分類パターンNo.１に区分けされる系統運用ケー
スNo.55で生じ、その値は次の通りとなる。
｜I〓Oc−I〓Oc(es)｜＝32.8A
自端の潮流条件によつて系統運用、パターンの
区分けを行なわず、第３表−(2)の運用ケース63種
に対して、演算誤差を最小化する定数K〓set a、
K〓set b、K〓set cに対する零相循環電流の演算誤差は分
類された系統運用パタン毎に定数を設定した場合
に比較して1.5倍〜2.0倍となる。
従つて、地絡故障検出感度を上げるために、自
端の電流条件によつて数種のパターンに分類し、
それぞれのパターンに対して演算誤差を最小化す
るような最適定数K〓a、K〓b、K〓cを系統シミユレー
シヨンによつて求める方法に著しい効果がある。
第３図は平行４回線系統の地絡保護方式の実施
例を示すものである。簡単化のために送電線は２
端子構成としているが３端子構成でも実施例の違
いはない。本発明による地絡保護リレーは電気所
S1端に設置されている。第３図で、１ａ−１Ｃは
３相電源、２は中性点接地抵抗器NGR、１１ａ
−１１ｃ及び１２ａ−１２ｃは母線、２１ａ−２
４ｃは送電線を示し、そのうち２１，２２，２
３，２４はそれぞれ１号（１Ｌ）、２号（２Ｌ）、
３号（３Ｌ）、４号（４Ｌ）回線とする。また、
３は電圧検出用変成器を示し母線のａ、ｂ、ｃ相
電圧E1（Ea，Eb，Ec）零相電圧E0を検出する。４
１ａ−４４ｃはしや断器を示す。５１ａ−５４ｃ
は電流検出用変流器を示し、送電回線１Ｌ，２
Ｌ，３Ｌ，４Ｌのａ，ｂ，ｃ及び零相電流I1L
（I1L a，I1L b，I1L c，I1L O）、I2L（I2L a，I2L b，I2L c
，I2L O）、I3L
（I3L a，I3L b，I3L c，I3L O）、I4L（I4L a，I4L b，I4L c
，I4L O）を検
出する。S2は相手端電気所、７は３相負荷を示
す。
１３は第１のデータ変換器を示し、変流器５１
ａ−５４ｃによつて検出された各回線の各相電流
I1L，I2L，I3L，I4Lを入力し、一定周期でサンプリ
ングを行ないデイジタル量に変換してそれらの量
S1を出力する。１４は第２のデータ変換器を示
し、変成器３によつて検出された母線電圧E1及
びE0を入力して、上記と同様の方法でデイジタ
ル量に変換してそれらの量S2を出力する。１５
は、地絡相検出器で、第２のデータ変換器１４の
出力である各相電圧信号S2を入力しそれらから地
絡相を検出し、その信号S2を出力する。
１６は系統運用パターン検出器で、第１のデー
タ変換器１３の出力である各回線の各相電流S1と
地絡検出器１５の出力S3とを入力して１線地絡故
障によつてほとんど変化しない中性点に対する健
全相電圧を基準とした各回線の健全相電流の有効
分の大小関係や電流なしの条件によつてあらかじ
め分類された系統運用パターンのいづれのパター
ンに属するか検出し、検出されたパターンを示す
信号S4を出力する。１７は定数出力器で、１６の
出力である検出された系統運用パターンS4を入力
して、あらかじめ系統シミユレーシヨンで求めら
れた前記の各パターンに対して零相循環電流の演
算誤差を最小化する定数K〓set a、K〓set b、K〓set cを
記憶
し、検出されたパターンに対する定数S5を出力す
る。
１８は零相循環電流演算器を示し、第１のデー
タ変換器１３の出力S1、地絡相検出器１５の出力
S3、定数出力器１７の出力S5を入力する。１Ｌ，
２Ｌの回線選択継電器に対しては、入力された信
号S3によつて健全相を知り、例えばａ相地絡なら
ば１Ｌと２Ｌとの健全相であるｂ相及びｃ相差電
流（I1L−I2L）をS1より演算する。さらに、この
健全相の２相の電流より正相分を除外し、この量
に定数出力器１７の出力S5から得た定数（ａ相地
絡ならばK〓set a）を乗じて零相循環電流を演算し、
その値S6を出力する。ａ相地絡で(6)式の演算を行
う。１９は補償部を示し、零相循環電流演算器１
８の出力S6、第１のデータ変換器１３の出力S1
（零相成分のみ）を入力する。１Ｌ，２Ｌの回線
選択継電器に対して、１Ｌと２Ｌとの零相差電流
（I1L−I2L）をS1より演算し、この演算値から零相
循環電流演算器１８で演算された零相循環電流の
演算値S6を差し引くことによつて地絡による中性
点抵抗器電流成分を導出する。この値S7を出力す
る。(8)式の演算を行う。２０は地絡回線選択器を
示し、補償部１９の出力S7及び第２のデータ変換
器１４の出力S2（零相電圧のみ）を入力し、零相
電圧を基準として補償部１９の出力である中性点
抵抗器電流S7の方向をみて地絡回線を選択し、そ
の回線のしや断器に対してトリツプ指令S8を出力
する。
次に、本発明の主要部である系統運用パターン
検出器１６、定数検出器１７および零相循環電流
演算器１８につきさらに詳しく述べる。１６，１
７は、系統運用パターン検出器及び定数出力器で
あるが、前記した通り(1)式で定義した定数K〓a、
K〓b、K〓cは系統運用状態に応じて個別の値をとる
ために、系統運用パターン検出器１６は第３表−
(1)に示すようにリレー設置端の各回線電流を測定
し、基準電圧に対する有効分の大小関係や、電流
なし等の条件によつて数種の系統運用パターン化
し、それら個々のパターンのいずれに属するかを
検出する。定数検出器１７は零相循環電流の演算
誤差を最小化する最適定数K〓set a、K〓set b、K〓set c
をあ
らかじめ系統シミユレーシヨンで求めておきその
値を記憶し、検出器１６で検出されたパターンに
対応する定数を出力する。第１図の系統で電気所
S2の回線２１，２２に設置する回線選択継電器に
対する系統運用パターン化条件と、それら個々の
パターンに対して系統シミユレーシヨンで求めた
最適定数を第３表−(2)に示すが、これについて具
体的実施例は次のようになる。地絡によつて影響
を受けない健全相電流を使う必要がある。回線２
１，２２，２３，２４のある健全回線電流をI〓21，
I〓22，I〓23，I〓24及び同一健全相の中性点に対する
電
圧を基準とした位相をθ21、θ22、θ23、θ24とする
と、第４図の系統運用パターン化フローのように
なる。
次に零相循環電流演算器１８は、地絡相に応じ
て２相の健全相差電流から正相分を除外した量に
地絡相に応じて選択した定数を乗じて零相循環電
流の演算を行う。回線選択継電器を設置する各相
差電流をI〓ad，I〓bd，I〓cdとすると演算フローは第
５
図の通りとなる。
以上述べた様に、平行４回線系統の相互インダ
クタンスの不平衡によつて発生する循環電流の性
質を利用して、系統の１線地絡故障時に２相の健
全相電流から正相分を除去した量に、各回線電流
の条件によつて、あらかじめ系統シミユレーシヨ
ンから求めた複数の特定な定数を選択して乗じて
零相循環電流を演算し、この演算値を使つて、継
電器に入力される零相電流に含まれる零相循環電
流を打ち消すことによつて、従来方式では成し得
なかつた平行４回線系統の高感度な地絡保護（第
１図の系統で従来形の約2.5倍感度が向上）が可
能となる。尚、電流入力を変えるだけで地絡方向
継電方式へ本発明は容易に適用できることは明ら
かである。[Table] As a result of calculating the calculation error for these optimal constants under the load conditions shown in Table 2, the maximum value occurs in grid operation case No. 55, which is classified into grid operation classification pattern No. 1. Its value is as follows. ｜I〓 Oc −I〓 Oc(es) ｜=32.8A Without dividing the system operation and patterns according to the power flow conditions at the own end, calculations were performed for the 63 types of operation cases shown in Table 3-(2). Constant K〓 set a that minimizes the error,
The calculation error of the zero-phase circulating current for K〓 set b and K〓 set c is 1.5 to 2.0 times as much as when a constant is set for each classified system operation pattern. Therefore, in order to increase the sensitivity of detecting ground faults, we classify them into several types of patterns depending on the current conditions at their own ends.
A method of finding optimal constants K〓 a , K〓 b , K〓 c that minimize the calculation error for each pattern by systematic simulation has a remarkable effect. FIG. 3 shows an embodiment of a ground fault protection system for a parallel four-line system. For simplicity, there are 2 power lines.
Although a terminal configuration is used, there is no difference between the embodiments even if a three-terminal configuration is used. The earth fault protection relay according to the present invention is
It is installed at the S 1 end. In Figure 3, 1a-1C is a three-phase power supply, 2 is a neutral point grounding resistor NGR, and 11a
-11c and 12a-12c are busbars, 21a-2
4c indicates the power transmission line, of which 21, 22, 2
3 and 24 are No. 1 (1L), No. 2 (2L), respectively.
No. 3 (3L) and No. 4 (4L) lines. Also,
Reference numeral 3 indicates a voltage detection transformer, which detects the a, b, and c phase voltages E 1 (E a , E b , E c ) and zero-sequence voltage E 0 of the bus. 4
1a-44c shows a breakout. 51a-54c
indicates a current transformer for current detection, and power transmission lines 1L and 2
a, b, c of L, 3L, 4L and zero-sequence current I 1L
(I 1L a , I 1L b , I 1L c , I 1L O ), I 2L (I 2L a , I 2L b , I 2L c
, I 2L O ), I 3L
(I 3L a , I 3L b , I 3L c , I 3L O ), I 4L (I 4L a , I 4L b , I 4L c
, I 4L O ) is detected. S 2 indicates the opposite end electrical station, and 7 indicates the 3-phase load. 13 indicates a first data converter, and a current transformer 51
Each phase current of each line detected by a-54c
Input I 1L , I 2L , I 3L , and I 4L , sample them at regular intervals, convert them to digital quantities, and calculate those quantities.
Output S 1 . 14 designates a second data converter, which inputs the bus voltages E 1 and E 0 detected by the transformer 3 and converts them into digital quantities in the same manner as described above to obtain these quantities S 2 . Output. 15
is a ground fault phase detector which inputs each phase voltage signal S2 which is the output of the second data converter 14, detects the ground fault phase from them, and outputs the signal S2 . 16 is a system operation pattern detector which inputs each phase current S1 of each line, which is the output of the first data converter 13 , and the output S3 of the ground fault detector 15, and detects a one-line ground fault. Detects which system operation pattern belongs to which is classified in advance based on the size relationship of the effective part of the healthy phase current of each line and the no-current condition based on the healthy phase voltage with respect to the neutral point, which hardly changes when and outputs a signal S4 indicating the detected pattern. 17 is a constant output device, which inputs the detected system operation pattern S4 , which is the output of 16, and minimizes the calculation error of the zero-phase circulating current for each of the above-mentioned patterns obtained in advance by system simulation. Store the constants K〓set a , K〓setb , and K〓setc , and output the constant S5 for the detected pattern. Reference numeral 18 indicates a zero-phase circulating current calculator, and the output S 1 of the first data converter 13 and the output of the ground fault phase detector 15
S 3 and the output S 5 of the constant output device 17 are input. 1L,
For the 2L line selection relay, the healthy phase is known by the input signal S3 . For example, if there is a ground fault in the a phase, the phase difference current between the b and c phases, which are healthy phases, between 1L and 2L (I 1L - I 2L ) is calculated from S 1 . Furthermore, the positive phase component is excluded from the current of the two healthy phases, and this amount is multiplied by the constant obtained from the output S5 of the constant output device 17 (K〓 set a if the a phase is grounded) to calculate the zero phase. Calculate the circulating current,
Outputs its value S 6 . Calculate equation (6) for the a-phase ground fault. Reference numeral 19 indicates a compensator, and the zero-phase circulating current calculator 1
8, the output S 6 of the first data converter 13, and the output S 1 of the first data converter 13.
(zero phase component only). For the 1L and 2L line selection relays, the zero-sequence difference current (I 1L - I 2L ) between 1L and 2L is calculated from S 1 , and the zero-sequence current calculated by the zero-sequence circulating current calculator 18 is calculated from this calculated value. By subtracting the calculated value S6 of the circulating current, the neutral point resistor current component due to the ground fault is derived. Output this value S 7 . Perform the calculation of equation (8). 20 indicates a ground fault line selector, which inputs the output S 7 of the compensator 19 and the output S 2 (zero-sequence voltage only) of the second data converter 14, and selects the output of the compensator 19 based on the zero-sequence voltage. A ground fault line is selected by looking at the direction of the neutral point resistor current S7 , and a trip command S8 is output to the line disconnector. Next, the system operation pattern detector 16, constant detector 17, and zero-phase circulating current calculator 18, which are the main parts of the present invention, will be described in more detail. 16,1
7 is a system operation pattern detector and a constant output device, and as mentioned above, the constant K〓 a defined by equation (1),
Since K〓 b and K〓 c take individual values depending on the system operation status, the system operation pattern detector 16 uses the values shown in Table 3-
As shown in (1), each line current at the end where the relay is installed is measured, and several types of system operation patterns are created depending on the size relationship of the effective portion with respect to the reference voltage and conditions such as no current. Detect whether it belongs to. The constant detector 17 determines optimal constants K〓 set a , K〓 set b , K〓 set c that minimize the calculation error of the zero-phase circulating current.
is determined in advance by systematic simulation, its value is stored, and a constant corresponding to the pattern detected by the detector 16 is output. Electrical station with the system shown in Figure 1
Table 3-( 2 ) shows the system operation patterning conditions for the line selection relays installed on lines 21 and 22 of S2 and the optimal constants determined by system simulation for each pattern. A practical example is as follows. It is necessary to use healthy phase currents that are not affected by earth faults. Line 2
The healthy line currents of 1, 22, 23, and 24 are I〓 21 ,
Assuming that I〓 22 , I〓 23 , I〓 24 and the phases based on the voltage with respect to the neutral point of the same healthy phase are θ 21 , θ 22 , θ 23 , θ 24 , the system operation patterning flow shown in Fig. 4 is obtained. become that way. Next, the zero-sequence circulating current calculator 18 calculates the zero-sequence circulating current by multiplying the amount obtained by excluding the positive phase component from the healthy phase difference current of the two phases according to the ground fault phase by a constant selected according to the ground fault phase. I do. If the phase difference currents for installing line selection relays are I〓 ad , I〓 bd , I〓 cd , the calculation flow is the fifth one.
As shown in the diagram. As mentioned above, by utilizing the properties of the circulating current generated due to the unbalance of mutual inductance in a parallel four-circuit system, the positive phase component is removed from the healthy phase current of two phases when a one-wire ground fault occurs in the system. The zero-sequence circulating current is calculated by multiplying the calculated amount by several specific constants determined in advance from system simulation according to the conditions of each line current, and this calculated value is used to input to the relay. By canceling the zero-sequence circulating current contained in the zero-sequence current, highly sensitive ground fault protection for parallel four-line systems, which could not be achieved with conventional methods, can be achieved. (improved). It is clear that the present invention can be easily applied to the ground fault direction relay system by simply changing the current input.
第１図は平行４回線送電系統図、第２図Ａ〜第
２図Ｃはそれぞれ第１図の平行４回線の電線配置
図、第３図は本発明の実施例に係る平行多回線地
絡保護方式のブロツク線図、第４図は系統運用パ
ターン化のフローチヤート、第５図は演算処理の
フローチヤートである。
１１〜１６……母線、２１〜２５……送電回
線、１３……第１のデータ変換器、１４……第２
のデータ変換器、１５……地絡相検出器、１６…
…系統運用パターン検出器、１７……定数検出
器、１８……零相循環電流演算器、１９……補償
部、２０……地絡回線選択器。
Fig. 1 is a parallel four-circuit power transmission system diagram, Fig. 2A to Fig. 2C are electric wire layout diagrams of the parallel four lines in Fig. 1, and Fig. 3 is a parallel multi-circuit ground fault according to an embodiment of the present invention. FIG. 4 is a block diagram of the protection system, FIG. 4 is a flowchart of system operation patterning, and FIG. 5 is a flowchart of arithmetic processing. 11 to 16... Bus bar, 21 to 25... Power transmission line, 13... First data converter, 14... Second
data converter, 15... ground fault phase detector, 16...
...System operation pattern detector, 17...Constant detector, 18...Zero-phase circulating current calculator, 19...Compensation unit, 20...Ground fault line selector.
Claims (1)
より得られる電気量を一定周期でサンプリング
し、デイジタル変換してこのデイジタル量によつ
て地絡保護する継電器に於いて、各回線の各相電
流の中性点に対する健全相電圧を基準とした各回
線の健全相電流の有効分の大小関係や電流なしの
条件によつてあらかじめ分類された系統運用パタ
ーンに属するかを検出して数種のパターンに分類
する系統運用パターン検出手段と、あらかじめ系
統シミユレーシヨンで前記の各パターンに対して
零相循環電流の演算誤差を最小化する定数を求め
て記憶し前記のパターン検出に応じて定数を出力
する定数出力手段と、前記系統に１線地絡故障が
発生した場合に地絡相を検出する地絡検出手段
と、２相の健全相回線間差電流を求めてこれらよ
り正相分を除外し、前記の定数出力手段から出力
された定数を地絡相に応じて選んだ値と前記の正
相分を除外した量を乗じて零相循環電流を演算す
る零相循環電流演算手段と、回線間差電流の零相
分から前記の零相循環電流の演算値をさしひいた
量を求める補償手段と、前記補償手段から算出さ
れた量の零相電圧に対する方向と大きさから地絡
回線を選択する地絡回線選択手段とを有し、この
地絡回線選択手段の出力によつて地絡回線のしや
断器を開路することを特徴とする平行多回線地絡
保護方式。1. In a relay that samples the amount of electricity obtained from the voltage transformer and current transformer of a parallel multi-line power transmission line at regular intervals, converts it into digital data, and uses this digital amount to protect against ground faults, each phase of each line is Several types of system operation patterns are detected by detecting whether the system belongs to a pre-classified system operation pattern based on the size relationship of the effective portion of the healthy phase current of each line based on the healthy phase voltage with respect to the current neutral point, and the no-current condition. A system operation pattern detection means for classifying into patterns, and a constant that minimizes the calculation error of the zero-phase circulating current for each of the above-mentioned patterns is determined and stored in advance through system simulation, and the constant is output in response to the above-mentioned pattern detection. a constant output means, a ground fault detection means for detecting a ground fault phase when a one-line ground fault occurs in the system, and determining the difference current between the two healthy phase lines and excluding the positive phase component from these. , a zero-sequence circulating current calculation means for calculating a zero-sequence circulating current by multiplying the constant output from the constant output means by a value selected according to the ground fault phase and an amount excluding the positive phase component, and a line. a compensating means for calculating an amount obtained by subtracting the calculated value of the zero-sequence circulating current from the zero-sequence of the difference current; 1. A parallel multi-line ground fault protection system, comprising a ground fault line selection means for selecting a ground fault line, and an output of the ground fault line selection means opens a break or a break in a ground fault line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7864682A JPS58195426A (en) | 1982-05-11 | 1982-05-11 | Parallel multichannel ground-fault protecting system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7864682A JPS58195426A (en) | 1982-05-11 | 1982-05-11 | Parallel multichannel ground-fault protecting system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58195426A JPS58195426A (en) | 1983-11-14 |
| JPH0210650B2 true JPH0210650B2 (en) | 1990-03-09 |
Family
ID=13667623
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7864682A Granted JPS58195426A (en) | 1982-05-11 | 1982-05-11 | Parallel multichannel ground-fault protecting system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58195426A (en) |
-
1982
- 1982-05-11 JP JP7864682A patent/JPS58195426A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58195426A (en) | 1983-11-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO1995024014A2 (en) | One-terminal data fault location system | |
| Yu et al. | Wide-area backup protection and protection performance analysis scheme using PMU data | |
| KR20090010536A (en) | System and method for determining areas of vulnerability for voltage sags assessment, and a medium having computer readable program for executing the method | |
| Phadke et al. | A new computer based integrated distance relay for parallel transmission lines | |
| EP0026620B1 (en) | Method and apparatus for identifying faults in electric power transmission systems | |
| Sidhu et al. | A power transformer protection technique with stability during current transformer saturation and ratio-mismatch conditions | |
| KR100782354B1 (en) | System and method for determining areas of vulnerability for voltage sags assessment, and a medium having computer readable program for executing the method | |
| EP0020073B1 (en) | Common suspension multi-line grounding protective relay | |
| JPH0210650B2 (en) | ||
| Sidhu et al. | A numerical technique based on symmetrical components for protecting three-winding transformers | |
| LV13922B (en) | Method for determination of distance to fault place by phase-to-earth fault in distribution networks | |
| JPH08265957A (en) | Matrix operation type system protector | |
| Hou | Comparing Fault Resistance Coverage of Different Distribution System Grounding Methods | |
| Bejmert et al. | Distance protection of block transformer units | |
| JP3024348B2 (en) | Distribution line fault section detection device | |
| JPH0532972B2 (en) | ||
| JP3278561B2 (en) | How to select the faulty line of the parallel transmission line | |
| Tran et al. | Numerical distance protection relay commissioning and testing | |
| JPS631810B2 (en) | ||
| Sachdev et al. | A technique for estimating the location of a transmission line shunt fault | |
| Kezunovic et al. | Design and Implementation of Overcurrent, Pilot, and Distance Protection | |
| CN110346689A (en) | The detection method of ground fault in neutral point non-direct grounding system | |
| JPS59204418A (en) | Trestle multichannel ground-fault protecting relay | |
| Chan | An investigation of grading margin violation in coordinating overcurrent relay/Chan Kok Wai | |
| JPS633536B2 (en) |