Obespvchete uninterrupted power supply t ‘l but logical equipment connected IA level Medium Voltage «* requires more reliable components, capable of! even in case of partial damage to continue the implementation of its functions. In full it can be attributed to high-power (over 1 kV) capacitor bank (CB) used to improve the power factor (cos v). Progress towards high specific electrical characteristics of the capacitors has always been a consequence of the emergence and use of more advanced materials and technologies. One of the main operational benefits of meta l loplenoch iyh capacitors (1) — self-healing dielectric system after local breakdown (self-healing) — possible to increase the energy efficiency of film capacitors by increasing the operating voltage of the electric field. Since the beginning of the 1990s, most kyzkovoltnyh (up to 1 kV) cosine capacitors (CC) is made of metal-razgychnym modification technology (1). However, KK average voltage (3-11 kV) having, compared with niekovoltnaii, much more of the stored and released in the process of self-healing energy, this technology * met with a number of problems. Only in recent years, pat, thanks to optimize the structure of plates, some electrical companies led to the production of metal-capacitors, designed for both high rated voltage and large capacity unit. These include and Electronicon Kondenaatoren GmbH, developed and commercially produced KK average naprvzheniv series M8D (2-4).
The active part of the group CC. floor general, our-occupier • Film «is wa tapes organic dielectric (non-polar polypropylene film) and the foil or netayalaziroaan-hemoglobin plates (hgtegtrodov) presuppositions calculation modelv Sapov capacitor 15) allow to adopt the following have forgiven ratio nekdu volume of its active part — V (CM1) in the basic electrical parameters:
V = (36stirlao -) / cF, (1) where C emnest capacitor (ICF); E is the electric field intensity (kV / cm); U-operating voltage of the I quarter); k is the relative permittivity spine.
From the formula (1) that by increasing the E to a value close to the maximum dielectric strength — £ ■ _ (in the range of 400-500 kV / mm for metallized polypropylene film ), mozhvo reduce material consumption iumenshit dimensions of power capacitor . Ceteris paribus increase in E only 10% will lead to a proportional increase in C reactive power to her film QC — Q = C * YU5 (quark) by 21%. but prtgkash rsshshytsvya this relnma ■ high QC (division of which £ «and the order exceeds the tension zaektrnchesiogo in other dx km to you and I to the Colt but of oboruloakivya g) associated with software-ki zvepluatatsaoavoy iadezh aostv. Take into account the importance of this issue, we consider in more detail the design ways to protect the dielectric saleny rktyh types of high plenochnp QC.
Today vile «barking market share of high-voltage capacitors occupy QC performed on all-film technology — a set of the same type of package, spiral wound sections having, in the spine depend on the desired electrical characteristics, in sleezvatelaoe. parallel or mixed compound (1a races). As the conductive plates sections ispolzuyutskh aluminum foil tape, handed over dividing their insulating seal ua polypropylene (thickness * 10 ykm) film, followed by impregnation cavities turns and zalolne npem residual volume of housing zhya-pgim ingredient — organic oil or synthetic fluid (races. 2). Typically, the exposed end of the foil is folded along the longitudinal collapse postroenve This film reduces internal heat outside the active part of your strength ■ iektrpg end connection sections, making them resistant to current grind lamas. Each section is provided with parallel connected fusible link in the form of a thin (0.25-0.35 mm diameter) copper wire, breaking section in case of breakdown (races 1a), supporting thereby further efficiency loss of the capacitor only some portion of its nominal capacity (1,5-546, depending on the reactive power QC [5 |).
Note that, unlike external protection fuses, fuse links sections destruction caused not by the energy coming from the network, and the energy stored directly vnutrn capacitor, its actual capacity proportionate . Therefore, when a significant loss of initial capacity, for example, because of the numerous outages, inserts the remaining sections KK are not melted in the desired time slot. Typical for all-film capacitor degradation capacity (including its skachveobraznoe drop at end of life) makes it necessary to control the symmetry of the capacitive load (differentsnalno faeoeoy-current protection) parallel | shunt) batteries of high JUS [2-4], as they have is much greater (compared with low-voltage KB) edkiichmaya reactive power. Washerwomen protection methods allow both circuit nssnmmstrni | 4], so in a constructive nyeresheniya | 5]. For example, some Tres CB-fayshe all-film spacecraft equipped ideas tnchnymv single phase capacitors, composed of two identical groups emaosta sections (common point sections soedknya etsd taken from one phase vomp ensafuen second Oktay and two drupk, through individual conclusions — vob- Šnē point N, a N,). The result is a connection scheme • CC double star * in * the ability to control the current imbalance between points CB N, in Nr
That * as a foil tolschaia Salov been accumulated with the second — a few microns, the vslsdstvas high conductivity of the electrodes and, respectively. Tova large faults formed at the breakdown and plates (2 races), connect the power Csete al-fim capacitors is allowed only through external tokosgravvchvvayuschne ala built-in fuses (PUE, ha. 5A.22). When an atom mime shsklmkay current external fuse on the condition of selectivity, ie willow bridge with plavknmv vstavkamv sekiay should be maaamun two cancer above par tion tova all- film hovdevsatora.
According Electrjcucon, agraty on komplezh tatsayu scheme aaschaty 6m tar her alb film KK co-constitute about 4Nk (for KB 10 World i) and 80 *) «(gave CB = 300 kvar) of the capacitor stonyostv.
Protection mstalloplsnochnyh capacitor *] in the (rvvs.3) uses a completely different taaopo-gicheskve principles * in the main of which — the ability samovosstanovveivya zlektriches Coy dielectric strength | 1 | Localization places breakdown mstahgshkatsva plates OBOP Chavan edge of a small (Sun more 0,00019b 11] ) the loss of the nominal capacity (up to the moment, that’s so you can fix the SCC tvchaos svizhenve capacity QC sulfuric MSD, must pronzoytv few thousand reteme Rat breakdowns). In addition, limiting the discharge power [1) — the concentration of the released and the breakdown point of thermal energy. s exceeding the limit lavaaoobrzhz-Vågå fracture plates, — contributes to high impedance electrodes as tslschvva sdoya klzsminievo tsinnovoy metal lvzatsav prvmervo 1 Ltd. times less than that of the foil.
Required nominal voltage QC Series MSD achieved a series connection of internal capacitive elements (16 races). Since the simultaneous breakdown iesaolkah elements is unlikely, and the breakdown of the PRV ode al th rest of them will be a kind of buffer soprotavdevaem about the value of time radium granichavayuschvm
Tayavm, the battery-netallools nochnmh QC Series VtSDpacx poavleiva aces