بەستەرکردنی دوبارەکاران و بڕگەکەسان لە تەرەسەداوەکانی پاشەکەوتی

Koordinasyonê Recloser û Sectionalizeran di Tirkêlên Dastrînê de

Recloser û sectionalizer automatîk (recloser û sectionalizer gerî bêtirîn) cihazên avtomatîkên tamm û bixweberên xwerûn. Wan dibejîn da ku hewceyên demkaran veqetandin nezîkî yên herî bixebit û çend an berfaran. Ji bo yekî recloser û sectionalizer di tirkêlên dastrînê de bikar anîn, wan dikarin hewceyên demkaran nezîkî yên herî bixebit vegerînin, ji bo ku nabeşin vegerebin be hewceyên demkarên pêvajoyî, u hewceyên demkarên pêvajoyî hatine izole kirin, li vir dibînin ku bixebitîna elektrikê zêdetir bike.

1. Fonksiyon û Xusiyetên Recloser Automatîk

Recloser automatîk cihazî avtomatîk e ku fonksiyonên parastina, detektîra, û kontrola hene. Li girtî wekhevî ya zamana-kerîdar ên din heye, ji bo ku divê çend an jî vegerîne. Ev cihazî tekmîl û taybetî ye ku breaker, parastina relay, û mekanîzmeya opereyonî integre kirin. Divê çend an jî detektîra kerîdar bi ser rûya serîla recloserê, u li dema ku hewceyek demkar detekt kiribit, li ser wekhevîya parastina zamana terbîhî li dema îro ya destpêkirî hewceyek demkar bigerîne û li ser bihêvekî ya çend an jî vegerîneka li ser rûya rêzeyê hewceyek demkar bigerîneke. Ji bo yekî hewceyek demkar nezîkî ye, lîneyek bi ser vegerînaya recloserê werdewej bibêje; ji bo yekî hewceyek demkar pêvajo ye, pasan recloser ên dema ku çend an jî vegerînek (sabita 3 jî) bigerîne û piştrast bike ku hewceyek demkar pêvajo ye, li ser kemanbigirîya otomatîk bigerîne û tu hewceyek demkar pêvajo heta dema ku hewceyek demkar rafike û kemanbigirîya çend an jî vegerînek bi ser destpêkirîya kemanbigirîyan ra werdewej bibêje.

Xusiyet û fonksiyonên taybetî yên recloser an jî:

• Li ser xusiyetên barkerda, recloser ên xusiyetên barkerda hewceyên demkarên qısa, çend an jî vegerînek, hilbijartina xusiyetên parastina sîstemî, û resetkirina sîstemê parastin hene.

• Recloser ên taybetî yên ark-chamber, mekanîzmeya opereyonî, sîstemê kontrol, coilê closing, û bîrçavên din hene.

• Recloser cihazê kontrola herêmî ye. Li ser xusiyetên parastina û kontrola, ên xusiyetên detektîra hewceyên xwe, daxwazîna xusiyetên kerîdar, operasyonên switching, û bi ser vegerînaya otomatîk werdewej bibêje, hesabkirina hejmara operasyonan, û operasyonên sîstema closing lockout hene. Ji bo recloserên bikar anîn li ser rûyan, tune cihaza opereyonî ekstra, û guça opereyonî wê direk ji lîneyek bixweberî hate cîh bide. Ji bo wan bikar anîn di substansiyonan de, guça bixweberî ya bicukî hane ji bo opening û closing ya mekanîzmeya opereyonî.

• Recloseran navçavan diha li ser tirkêlên dastrînê de saz kirin, û wan di substansiyonan de ne diha li ser polên din ne saz kirin.

• Hejmara operasyonên locking, xusiyetên zamana opening, û operasyonên sîstemê çend an jî vegerînek li ser recloseran yên din navçavan din ne. Xusiyetên nasnameyî yên breaking operation û 3 reclosing operation: break → (T₁) close - break → (T₂) close - break → (T₃) close - break, ku T₁ û T₂ adjustable ne û bi nav recloseran navçavan din girîng din. Divê hejmara operasyonên çend an jî vegerînek û interval time ya çend an jî vegerînek li ser bizîya bikar anîn biguherîne.

• Breaking phase-to-phase fault recloser ên xusiyetên zamana terbîhî bikar anîn ji bo ên xusiyetên ampere-time ya fuses (lê breaking ground fault recloser ên controlled electronically xusiyetên definite time limit bikar anîn). Recloser ên du xusiyetên ampere-time curve hene: fast û slow. Li ser çend an jî breaking operation ên yekem, ên xusiyetên fast curve bikar anîn, ku hewceyek demkar bi ser 0.03 - 0.04s digerîne. Ji bo operasyonên breaking din, xusiyetên ampere-time curve navçavan dikarin hilbijartin li ser bizîya coordination.

2. Fonksiyon û Xusiyetên Sectionalizer Automatîk

Sectionalizer cihazê parastina automatîk e ku di tirkêlên dastrînê de bikar anîn ji bo izolasyona hewceyek demkar line. Li ser bikar anîn diha ji bo yekî recloser automatîk û breaker. Sectionalizer tune hewceyek demkar barkerdek. Ji bo yekî hewceyek demkar di line sectioned de were, recloser ên backup protection û breaker ên sectionalizer operate, û funksiyon ên counting ên sectionalizer start bike ku hejmara tripping operations ên recloser hesab bike. Ji bo yekî sectionalizer hejmar ên preset ên recorded operations weregihet, li ser dema ku device ên backup trip bike, li ser hewceyek demkar line faulty disconnection bike. Recloser çend an jî vegerîneke bi ser rojane power supply line din. Ji bo yekî hejmar ên tripping operations ên recloser tune hejmar ên preset ên recorded operations ên sectionalizer ne û hewceyek demkar rafeke, hesabkirina sectionalizer li ser dema ku tune bi ser rojane automatic reset bike, li ser initial state.

Sectionalizers diha navçavan li ser hejmara phase: single-phase û three-phase. Li ser control method, ên divide hydraulic control û electronic control. Sectionalizers ên controlled hydraulically use hydraulic control for counting, while electronically controlled sectionalizers use electronic counting. Main functions and features of automatic sectionalizers are as follows:

• Sectionalizers have the function of automatically counting the number of tripping operations of the upper-level protection device.

• A sectionalizer cannot isolate fault currents, but it can disconnect permanent line faults in cooperation with a recloser. Since it can isolate full-load currents, it can be used as a manually operated load switch.

• A sectionalizer can perform automatic and manual tripping. After tripping, it is in a locked state and can only restore power supply through manual closing.

• A sectionalizer has a tripping coil connected in series in the main circuit, and the minimum operating current can be changed by replacing the coil.

• There is no mechanical or electrical connection between a sectionalizer and a recloser, and there is no restriction on its installation location.

• A sectionalizer does not have an ampere-time characteristic, so it has special advantages in use. For example, it can be used in occasions where the protection characteristic curves of two protection devices are very close, thus making up for the defect that coordination cannot be achieved sometimes even by adding steps in a multi-level protection system.

3. Cooperation Between Reclosers and Sectionalizers

The cooperative operation of reclosers and sectionalizers can realize the elimination of transient faults, the isolation of permanent fault areas, and ensure the normal power supply of non-faulty line segments. Due to the different functions of reclosers and sectionalizers, first, the section layout of the line should be reasonably determined according to the system operation conditions to improve the degree of distribution line automation and power supply reliability. Its typical structure is shown in Figure 1.

Theoretically speaking, each branch point on the line should be considered as a sectioning point. In this way, even if a permanent fault occurs on a relatively short branch line, it can be selectively sectioned, and the normal power supply of other sections can be maintained. However, due to economic and operating condition constraints, it is often impossible to achieve this. Therefore, it is necessary to proceed from reality and adapt to local conditions. Both reclosers and sectionalizers are intelligent devices with many advantages such as a high degree of automation. However, they can only play their roles when used in correct coordination. Therefore, the following coordination principles should be followed:

• The sectionalizer must be connected in series with the recloser and installed on the load side of the recloser.

• The backup recloser must be able to detect and act on the minimum fault current within the protection range of the sectionalizer.

• The starting current of the sectionalizer must be less than the minimum fault current within its protection range.

• The thermal stability rating and dynamic stability rating of the sectionalizer must meet the requirements.

• The starting current of the sectionalizer must be less than 80% of the minimum tripping current of the backup protection and greater than the peak value of the expected maximum load current.

• The number of recording times of the sectionalizer must be at least 1 time less than the number of tripping times of the backup protection before locking.

The memory time of the sectionalizer must be greater than the total accumulated fault breaking time (TAT) of the backup protection. The total accumulated time (TAT) of the backup protection action is the sum of the fault current-carrying time of each fault in the backup protection sequence and the reclosing interval. Since the sectionalizer does not have an ampere-time characteristic, the coordination between the recloser and the sectionalizer does not require the study of protection curves.

The backup protection recloser is set to lock after 4 tripping operations. These operations can be a combination of any fast and slow (or delayed) operation modes, and the setting number of times for the sectionalizer is selected as 3 counts. If a permanent fault occurs on the line on the load side of the sectionalizer, the sectionalizer will open to isolate the fault before the 3rd reclosing of the recloser, and then the recloser will supply power to the non-faulty line. If there are other serially configured sectionalizers, the number of locking times they are set with should be smaller level by level.

When a fault occurs on the line on the load side of the last-stage sectionalizer, the recloser acts. The serially connected sectionalizers all record the number of times the recloser breaks the current. After the last-stage sectionalizer reaches the number of action times, it trips to isolate the fault, and then the recloser recloses to connect the non-faulty line and restore normal power supply. The sectionalizers that do not reach the number of counting times will reset to the initial state after the specified reset time.