PROGRESS IN THE POWER QUALITY INDICATORS SYSTEM

Transcription

1 BLETINL INSTITTLI POLITEHNIC DIN IAŞI Publicat de iveritatea Tehică Gheorghe Aachi di Iaşi Volumul 63 (67), Numărul 1, 017 Secţia ELECTROTEHNICĂ. ENERGETICĂ. ELECTRONICĂ PROGRESS IN THE POWER QALITY INDICATORS SYSTEM BY VIRGIL MAIER, SORIN G. PAVEL ad HORIA G. BELEI * Techical iverity of Clu-Napoca, Romaia Received: February 15, 017 Accepted for publicatio: March, 017 Abtract. The Power Quality i appreciated by a idicator ytem, made up of a et of characteritic parameter, ome of which ca be ormalized. Oe of the recogized propertie of the idicator ytem i the perfectibility, which i upported by a erie of recetly publihed article by the paper author. Regardig the variatio of the voltage r.m.. value, it i propoed to highlight ad eparate the voltage variatio due to itervetio actio performed or recorded at the level of the dipatcher. I thi way, fewer harmoic of voltage low variatio remai to be iterpreted. Recoiderig the calculatio relatiohip of voltage fluctuatio better reflect the viual perceptio pheomeo. Differece obtaied by uig the propoed formula will igificatly affect the value of the flicker idicator. The propoed characteritic parameter for voltage ag ad overvoltage complete the idicator family of the voltage r.m.. value, ome of which will be ormalized i the future. Key word: power quality; voltage low variatio; voltage fluctuatio; voltage dip; overvoltage. 1. Itroductio Amog apect related to power quality (PQ), the voltage variatio ad hape are prioritie i the relatiohip betwee upplier ad ed-uer (Maier, * Correpodig author: horia.beleiu@em.utclu.ro

2 3 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu 003). Although the characteritic variable are defied for differet type of voltage variatio, with relatiohip propoed for their calculatio, there i o ytematic way to aalyze voltage variatio by ow, leadig to iterpretable cocluio ad appropriate compeatory meaure (Arrilaga, 000; Duga, 003). Alo ome computatioal relatiohip are quetioable (IEC , 1997), whe real pheomea modellig i deired through more accuracy. Although literature recogize that for ome Power Quality (PQ) diturbace iufficiet idicator are defied (Golovaov, 001), o propoal have bee made for thee, oly i author work. The etwork voltage variatio, uder or over the voltage rated value are moitored both a r.m.. ad itataeou value. A r.m.. value, the workig voltage ca be either periodically higher tha the rated oe, i the frame of voltage low variatio (VSV) or the rapid oe, alo called voltage fluctuatio (VFL), or o-periodically, but with igificat decreaig or icreaig related to the rated voltage, apect deigated by the term of voltage ag (VSG or dip) ad of hort time overvoltage (STOV), repectively (Arrilaga, 000; Hae, 000). The eceity of a expreive aalyi of voltage variatio led to idea of the voltage wave decompoitio i actio ad harmoic that repreet a ew cocept of voltage variatio aalyi. The uitary tep actio are equivalet to a ifiite harmoic umber. I term of electric power ytem thee actio are foud i the itervetio of the dipatcher, upplier or eduer for maitaiig the r.m.. voltage withi limit. The highlightig of voltage wave level ad the the modulatio harmoic aalyi of the voltage variatio i proved to be the mot accurate method of VSV aalyi (Leşe, 01). Some of voltage r.m.. diturbace are o-periodic ad uilateral, like VSG ad STOV, oly that they are i the oppoite ee: while the VSG repreet a igificat decreaig of the workig voltage uder the rated value, STOV repreet a igificat overcomig of the rated value by the workig voltage, oe. The overvoltage mai coequece i the iulatio tre which, from ome voltage value ad i ome coditio, ca be pierced; i additio, ome receiver ca tep i overload regime (Maier, 016b).. Voltage r.m.. Value Variatio.1. Baic Idicator of VSV The periodic r.m.. voltage variatio ca be low variatio, coitig i deviatio up to 0% of it rated value ad with the periodicity i the iterval of (5 mi4 h) ad fat variatio, called fluctuatio, with deviatio up to 10% ad periodicity i the rage of (40 m5 mi) (Maier, 01). To appreciate the VSV, alo called voltage irregularity, idicator are ued to expre the voltage deviatio from it omial value,, pecific to

3 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, each power ytem egmet (Beleiu, 010). The real voltage, i coidered poit of the etwork ad i the pecified momet i called workig voltage,, ad ice the ue of relative quatitie i expreive ad coveiet, the parameter amed relative workig voltage u or voltage level i itroduced by the relatio: u, (1) which ca be ued a above or i percetage expreio. The PQ idicator for VSV are cocetrated i Table 1, veru the r.m.. voltage, a abolute parameter ad veru it relative value, the percetage workig voltage ad the voltage level u (relatio 1). Parameter u % 100, [%] () Table 1 Calculu Relatio of VSV Specific Idicator, i Relatio to the Abolute ad Relative Voltage Workig voltage, [V] Workig voltage percetage, u % 100 /, [%] Voltage level u / NT Voltage 1 mea N k N T N 1 1 T u% u% k u T k uk 1 NT k 1 NT k 1 Voltage deviatio,[v] u u 100,[%] 1 % % u u Voltage N 1 T N 1 T N 1 mea ktk,[v] u % u % ktk,[%] deviatio T0 k u T k k 1 T0 k u T 1 T0 k 1 Square N 1 T N 1 T N 1 T mea ( k ) Tk ( u % k u %) T k ( u u ) T deviatio T0 k 1 T0 k 1 T0 k 1 Voltage variatio C C u% u% C u u coefficiet u% u.. Method of VSV Aalyi k k Recet tudie performed by the author (Leşe & Maier, 01) led to the idea of the voltage wave decompoitio firt i actio ad the i harmoic. A actio, are coidered all techical itervetio of the dipatcher, the upplier or the ed-uer i the power ytem to maitai the r.m.. workig voltage i the precribed tadard. The actio are othig-all

4 34 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu or 0-1 type i biary, which may be characterized a duratio ad actio mode through uitary tep fuctio. The appreciatio of the gap produced by actio require previou quatitative aemet of the voltage variatio moitorig ad aalyzig proce to allow caue-effect type idetificatio. Graphically, the actio fuctio are repreeted a uitary tep igal, for which a geeral form ha bee coidered ad the correpodig Fourier developmet, coitig of a ifiite amout of harmoic ha bee alo determied. The harmoic decompoitio of the of uitary tep fuctio argue, a a firt tep i the VSV aalyi, the emphaizig of the "othig-all" or "0-1" actio, thee oe correpodig to the cotiuou compoet. It i kow that the dc compoet i the Fourier aalyi i determied by the relatiohip (Maier, 01): 0 p1 1 k, [V], (3) p k 0 where: (p) i the total umber of ample (value) for the coidered period equal to the obervatio time; k a ample parameter, equal i thi cae with the voltage r.m.. value or with oe of the medium voltage value, o very hort (3) or hort time (10 mi) iterval. Fig. 1 how the et of four fictive level poited out o a variatio of the workig voltage wave. Each level i i characterized by the mea quare, i {1,, 3, 4}, which may be ituated above or below the rated value pi a well a the correpodig begiig momet t i0. Further o, the Fourier aalyi of the coidered voltage variatio i highlightig the mai modulatio harmoic of the VSV with a periodicity greater tha 5 mi, a a expreio of ome periodical actio withi the power coumptio. Fig. 1 The highlighted level i the voltage variatio graph, o the obervatio period, for a day ad their time iterval.

5 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, Fially, the voltage variatio that are ot utified either by actio or by load variatio ca be attributed to voltage variatio i the etwork upplyig poit, dowtream the oe where the voltage loe were coidered by calculatio. The aalyi of procee which take place at the ed-uer upplied from the ditributio poit repreeted by the meauremet poit would be revealig the exitece i techological procee of thoe periodicitie, which have maifeted with trikig i the low voltage variatio. The iterpretatio of differece betwee level or tep might be doe i better coditio, if a itervetio lit would exit at the territorial dipatcher level, uder which the moitored poit of coumptio i alo located ( , 004). A ome actio, uch adutig witche plot, take place without the itervetio of the huma operator, idetifyig them i relatively difficult ad require complex moitorig of the power ytem..3. Voltage Fluctuatio ad the Flicker Pheomeo Fluctuatio or voltage fat variatio repreet the r.m.. or peak value (amplitude) variatio of the voltage wave, i the limit of 10%, produced i the frequecy rage of ( ) Hz, which correpod to periodicitie i the rage (40 m...5 mi). The voltage fluctuatio amplitude i defied by the relatiohip (Maier, 01): 1 100, [%], (4) where: ad +1 are two coecutive ad differet value of the voltage amplitude ad repreet the r.m.. of the correpodig rated voltage; reportig to amplitude wa preferred becaue thi oe i eaier to be idetified aalytically or graphically. To ote that the voltage fluctuatio amplitude i a poitive quatity ad two or more voltage fat variatio, which occur i le tha 30 m, may be coidered a oe variatio. The amplitude of the maximum allowable voltage fluctuatio are ormalized accordig to their hape ad frequecy. Thee amplitude fall betwee 0.3% at the 8 Hz frequecy ad 3% at the Hz frequecy i the cae of iuoidal variatio. Flicker term, a i adopted eve i Romaia Stadard, defie the impreio of viual eatio itability produced by a light timulu whoe lumiace or pectral ditributio fluctuate with time. Coiderig voltage a the caue of viual perceptio variatio, flicker idicator, uch a flicker doe ad flicker everity (Golovaov, 001), are baed o the defiitio (4) of the voltage fluctuatio amplitude. It hould be oted that the relatiohip (4) doe ot correctly model the flicker pheomeo, i accordace to the tadard defiitio. Thi i becaue it ha o ee to report the voltage variatio to the rated voltage, takig ito accout that the huma eye ad brai do't have et the perceptio at uch a

6 36 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu referece parameter. A more correct modelig of the viual perceptio impoe to ue the viual eatio from the momet t (whe the voltage amplitude i ) a referece parameter. So, the followig relatiohip i propoed (Maier, 01), 1 100, [%], (5) which lead, obviouly, to differet reult from thoe obtaied by the relatio (4), epecially whe < +1. The compario of reult obtaied with relatiohip (4) ad (5) i made for the cocrete cae of the followig voltage wave (Maier, 015): u t 1 0.0i 50 t / 3 30 i100 t, [V], (6) 0.05i 100 t / 3 which imulate a idutrial frequecy voltage, modulated by amplitude with 5 Hz ad 16.7 Hz. a b Fig. Aalyzed voltage waveform; a itataeou value o firt 0.1 ; b voltage amplitude highlightig.

7 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, The ocillogram from Fig. a preet the voltage wave apect durig the firt 0.1, meawhile the voltage abolute value u i emphaized i Fig. b i order to highlight the voltage coecutive amplitude. The two modulatio voltage, imulated i the bracket from relatiohip (6), have the amplitude of % repectively 5% of the rated voltage amplitude, at the idutrial frequecy. The voltage amplitude value, calculated with (6) for the firt a well a the voltage fluctuatio amplitude, for three differet ituatio, are preeted i Table. The time value from the firt table lie idicate the momet where the voltage wave amplitude are regitered. O the ecod lie the voltage amplitude i are pecified, i abolute value, coidered for the ituatio whe the r.m.. value i quite the rated value, =30 V. Table Voltage Fluctuatio Amplitude No. Parameter Time-voltage coordiate of the amplitude 1 t, [m] , [V] i 3, [V] , [%] , [%] , [%] Aalyzig the rectified ocillogram of the voltage wave (Fig., b), the i voltage amplitude value a well a the tadard recommedatio of mergig the mall variatio that occur withi a rage le tha 30 m, leaded to highlightig the differet voltage amplitude i the 3 rd lie of Table. Further o, the voltage fluctuatio amplitude were determied i % uig relatiohip (4), through reportig the differece betwee voltage coecutive amplitude to the rated voltage amplitude M V. The quare mea of thee fluctuatio amplitude o the coidered rage i: 1 6 med 1 5, % (7) The voltage fluctuatio amplitude, calculated with the propoed relatiohip (5), a a adaptatio to the flicker pheomeo defiitio, are icluded o the 5th lie of the Table. The relative differece, i percetage, betwee (calculated with rel. 4) ad (calculated with rel. 5) are framed i the rage 4, 5%. The quare mea of the fluctuatio amplitude, with reportig to the previou value, o the ame iterval, i: 1 6 med 5.89%, (8) 6 1

8 38 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu which differ by le tha oe percet (0.66%) veru the value give by relatiohip (7). Aother importat obervatio, regardig the ue of relatiohip (4) for the fluctuatio amplitude, i that while it umerator ca vary proportioally with the workig voltage, a a reult of the voltage adutig actio, the deomiator remai cotat. Thi ituatio i reflected i the 6 th lie of Table, whe the workig voltage wa coidered 5% higher tha the rated voltage. Therefore, for the voltage fluctuatio amplitude the followig relatiohip i coidered: 1 105, [%], (9) which lead to value of the correpodig fluctuatio amplitude higher tha value (the 4 th lie, Table ); it doe ot happe whe uig the propoed relatiohip (5). The quare mea of thee fluctuatio amplitude, o the ame iterval, i ( + ) med = 6.075%, which i 3.14% higher tha the mea () med, calculated accordig to the relatiohip (8). The relatiohip (4) eitivity at workig voltage variatio, a how above, i aother argumet of uig the propoed relatiohip (5), baed o reportig the voltage or lumiace variatio to the correpodig previou value..4. The flicker doe The effect i time of the lumiace fluctuatio over a huma ubect i more accurately etimated by the flicker doe tha through the fluctuatio amplitude. The etimatio of the voltage fluctuatio ifluece i ormalized to be made i accordace with the cumulative priciple, baed o recordig the eye accumulated fatigue up to the doe whe work become impoible (Maier, 01). The reaoig i baed o the equivalece of fluctuatio havig the frequecy f i ad the amplitude fi with a fluctuatio havig the 10 Hz referece frequecy ad the equivalet percetage amplitude ( 10) i g fi fi, [%], (10) i order to determie a idetical dicomfort; the fluctuatio equivalece coefficiet g fi are experimetally determied i report with the ource type ad the fluctuatio frequecy. Overlappig the effect of differet frequecy fluctuatio i realized with the relatiohip: fi fi g [%], (11) 10, i ad the flicker doe i defied through the relatiohip:

9 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, T0 F 10 t 0 d, (%) mi, (1) where: T 0 repreet the diturbace etimatig duratio. The flicker doe expree the total dicomfort, which i felt by the huma eye o the T 0 duratio, beig ormalized i the value-duratio coordiate. Relatig to the itegral relatiohip (1), the followig obervatio ca be formulated: a) kowig the modulatio voltage fi require a Fourier aalyi for the correpodig wave of the r.m.. voltage value, o a miimum 5 mi. iterval, which correpod to the maximum periodicity of the tadardized voltage fluctuatio; b) a itataeou value of the equivalet percetage amplitude 10 doe ot exit; but we ca peak oly about a valid value o the properly Fourier aalyi rage; c) the itegral relatiohip of the flicker doe defiitio caot be accepted eve at limit. Coequetly, thi itegral form ha to be replaced by the relatio (Maier, 015): N k k 1 T, (%) mi, (13) F 10 k 0k where: 10 k repreet the equivalet percetage amplitude o the voltage wave aalyi iterval k, havig T 0k duratio of miimum 5 mi; N k umber of the Fourier aalyi iterval, o the etire obervatio time T 0 : T N k T, [mi]. (14) 0 0k k1 A i the cae of the voltage fluctuatio amplitude, the flicker doe exemplifyig i term of value i coidered edifyig. For thi, the reultig modulatio voltage i coidered havig the form a the oe cotaied i bracket i relatiohip (6), icludig the modulatio harmoic a follow: i) a modulatio harmoic with f 1 = 5 Hz frequecy, havig f1 = = 0.% amplitude, for which the equivalece coefficiet ha the value g f =0.836; ii) for the f = 16.7 Hz frequecy, the modulatio harmoic ha the amplitude f = 0.5% ad the equivalece coefficiet g f = It come out that modulatio harmoic were adopted with amplitude te time maller tha i the cae of determiig fluctuatio amplitude, where the graphical highlightig of the voltage wave amplitude repreeted a methodological eceity. Further o, the percetage equivalet amplitude 10 i determied (relatiohip 11):

10 40 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu 10 ( ) ( ) %. (15) Calculatig the flicker doe with relatiohip (13), for a obervatio rage T 01 =15 mi, it will be obtaied: F ( ) 1T (%) mi, (16) that exceed more tha.3 time the correpodig admiible value ε Fadm = 1.3 (%) mi (Maier, 01)..5. Voltage Sag VSG repreet igificat decreae of (10 90)% of voltage r.m.. value, o hort time period betwee (10 m 3 ) (Duga, 003). I other word, durig VSG the relative workig voltage i ituated i the iterval u [ ]. There are opiio ad eve tipulatio which lower the VSG iferior limit till zero, but thi mea already the voltage abece ad o of the electrical power (Maier, 01). Practically, oe caot peak about a poor quality of a product (here, electrical power), foud i uavailability (abet). For the ame reao, either the iterruptio, beig eve hort term, caot be icluded i PQ iue, thee oe beig uder the quality of the electrical power upply ervice. VSG durig more tha 3 are alo icluded i iterruptio category (Arrillaga, 000). VSG aalytical idicator, kow from the literature, are their amplitude, duratio ad frequecy (Golovaov, 001). Further o, for defiig ome additioal idicator for the VSG, i adopted the impler hape, cloe to the quadrilateral oe, amely the triagular hape VSG, accordig to the repreetatio from Fig. 3. Fig. 3 VSG of triagular hape ad the mai characteritic parameter.

11 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, The VSG recordig algorithm tart whe the workig voltage value drop below = 0.8, correpodig to the poit C from the voltage r.m.. graphic, o the time variable parameter, from thi momet, ca be retaied a beig importat ad propoe for thi the term "VSG cofirmatio time" ad the otatio t cf (Fig. 3). Goig back i the data file, the momet whe the voltage paed through the value = 0.9 i earchig, thi becomig the iitial momet t i of the VSG (poit B, Fig. 3). After reachig i poit D the miimum value gmi, the workig voltage i tartig to icreae for reachig the value = 0.9 i poit F, of which abcia will repreet the VSG fial momet t f. Baed o thi repreetatio, the completio of the VSG characteritic idicator i propoed with the followig parameter (Maier, 016 a): -relative voltage ag maximum amplitude Δu gm, correpodig to the time momet t mi, whe the workig voltage reache the miimum value gmi, calculated with the relatiohip g m i u g M 1 0 0, [%], (17) but where the differece of the umerator wa take i abolute value, coiderig that the repective parameter preet more expreivity, i rederig the voltage decreaig depth, i ratio with the rated value; voltage ag decreaig lope, durig the VSG, give by the relatiohip: 0. 9 t t m i t i g g m i, [V/]; (18) voltage ag recoverig lope, from the miimum value gmi, to the rated voltage value, 0. 9 t t f t g g m i R m i, V/, (19) the udelivered degree, for which i propoed the followig relatiohip: G N T T, (%), (0) k k k expreig, to a certai degree, the udelivered electrical power durig the VSG, relative to which ca be appreciated the VSG coequece. I the relatiohip (0), N T repreet the fudametal period umber, highlighted o the VSG duratio t g, the curret period havig the duratio T k ; voltage irregularity degree durig the VSG, for which i propoed the relatiohip:

12 4 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu G N 1 T k T, (%) ; (1) k t g k dageroue fuctio of the voltage ag, howig the depedece betwee the workig voltage value durig the ag, with value i the rage [ gmi (0.9 )] ad the abece of that voltage value, i the fuctio form of t g ( ). For exemplificatio, two repreetative poit, from the propoed graphic, ca be highlighted i the ee of idicatig the coordiate pair abcia (workig voltage) ordiate (duratio, Fig. 3): ((0.9 ), t g ) ad ( gmi, 0); mea relative voltage, durig the ag, give by the relatiohip: u g 1 N T k Tk t k g. () 1 The eceity to itroduce the maximum, relative amplitude of the VSG Δu gm (relatiohip 17) i that ome VSG coequece are determied preciely by thi idicator. Decreaig, repectively recoverig lope of the workig voltage durig a ag capture the dyamic performace of the ag, allowig a evaluatio of a VSG overall coequece, correlated with the maximum, relative amplitude ad with the VSG duratio. I additio, the recoverig lope of the workig voltage (Δu g /Δt) R repreet a warig for poible caue of workig iulatio pucture..6. Short Time Overvoltage STOV repreet icreae of the workig voltage r.m., i the rage of ( ), for time iterval of (0.5T 1 mi), where T repreet the fudametal period. The STOV repreet PQ diturbace with igificat ecoomic coequece, both for ed-uer ad for upplier alo (Rya, 001). Curretly, there are defied too few characteritic parameter of thi oe, iufficiet for a correct aemet of their coequece. The cietific bai for defiig ew idicator for STOV i repreeted by the electrical iulatio tree. Overvoltage ca be characterized, i a firt tage, by the relative workig voltage (or voltage level) u, (3) parameter which wa choe eve for the graphic repreetatio of a STOV geeral profile u (t), how i Fig. 4. The poit A i coidered the iitial momet of STOV (Fig. 4) with t i a abcia, whe the workig voltage exceed with 10% the rated voltage ad the lope of the workig voltage variatio, i thi poit, i maitaied poitive (Maier, 01).

13 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, Durig the STOV, the workig voltage reache a maximum value SM (Fig. 4), that ca exceed up to 80% the repective rated voltage; t M repreet the momet whe thi maximum value i reached. From thi maximum value the workig voltage tart to decreae to the poit D, with a cotat or variable lope, whe the value (1.1 ) i reached agai, but thi time dowward the voltage variatio; the D poit abcia i called the fial time t f of the STOV (Maier, 016b). The quadrilateral profile of a STOV (Fig. 4) geeralize the practically poible cae, exitig a direct lik betwee the caue that produce the overvoltage ad it time profile, a i VSG cae. Fig. 4 Voltage variatio durig a hort time overvoltage ad the mai characteritic parameter. I practice i preferred the percetage expreio of the relative workig voltage, give by relatiohip: u % 100, [%]. (4) The voltage percetage deviatio (Maier, 01), give by the relatiohip: u % 100, [%], (5) ad the overvoltage duratio t, determied a differece betwee the fial ad iitial time (Fig. 4): t S t f ti, [] (6) are belogig to the coecrated idicator of STOV. Give the above tatemet, the followig idicator for STOV will be added further o, by aumig the repoibility for their future utility ad perfectibility (Maier, 016 b):

14 44 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu overvoltage maximum amplitude SM (Fig. 4), recorded at the momet t M, a expreio of the electric iulatig material tree from their dielectric rigidity viewpoit, expreed either i abolute value (Volt), or related to the rated voltage, i percetage: u SM SM % 100, [%] ; (7) medium relative overvoltage (weighted by time), give by the relatiohip: u S N T 1 T, t (8) S where: i the idex for the curret fudametal period, of T period, durig which the workig voltage r.m.. i determied ad N T i the umber of fudametal period, o the overvoltage duratio t S ; icreaig lope of the workig voltage, durig the overvoltage, a itataeou value, maximum ad medium. A itataeou value, the voltage icreaig lope i determied with the relatiohip: t S 1 1 T 1, [V/], (9) ad from their trig value the maximum value (Δ S /Δt) M i idetified, repreetig the recorded maximum lope. Regardig the voltage icreaig medium lope the followig relatiohip i propoed: 1.1 t t t S SM med tre level, defied through the followig relatiohip: M i, [V/]; (30) N T S T, (%), (31) expreig with a certai irregularity degree the additioal eergy, lot i iulatio or i electrical coductor durig the overvoltage. I the relatio (31), N T repreet the umber of fudametal period, highlighted o the overvoltage duratio t S, the curret fudametal period havig the duratio T ; voltage irregularity degree durig the overvoltage, for which i propoed a relatiohip imilar with the oe propoed for VSG (Maier, 01): S 1 NT 1 T t, (%), (3) S 0.01

15 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, writte i the dicreet character hypothei of the (t) fuctio, determied by the data acquiitio type. Reao for which to defie additioal idicator for STOV wa coidered appropriate derive from the eceity of evaluatig their coequece over the iulatio, electrical itallatio ad equipmet. Thu, the overvoltage maximum amplitude SM, the maximum icreaig lope of the overvoltage poitive frot (Δ S /Δt) M ad the tre level λ S preet a importat iteret i order to characterize the STOV ifluece o iulatio. Regardig the overload type tree, which occur durig the overvoltage at the reitive ad iductive receiver ad capacitor alo, the followig idicator are coidered importat: the medium relative overvoltage u S, the tre level λ S ad the voltage irregularity degree, durig the S overvoltage. 3. Cocluio Through the ucceive cotributio of recet work, the PQ idicator ytem developmet for the voltage r.m.. variatio became importat ad remarkable. Defiig ad applyig the cocept of voltage wave decompoitio, idicatig the r.m.. value of voltage variatio, i the actio ad modulatio harmoic repreet the baic idea of the VSV aalyi. Graphically, fuctio correpodig to the actio are repreeted a uitary tep igal, for which a geeral form wa coidered ad the correpodig Fourier developmet wa determied, coitig i a ifiite amout of harmoic, but i a certai relatio of amplitude ad phae. A ew relatiohip wa propoed for voltage fluctuatio calculatio which realize a more correct modelig of the huma eye viual perceptio. Alo, a um form relatiohip i propoed for the flicker doe calculatio, takig ito accout that a harmoic aalyi of the modulatio voltage i impoible o ifiite mall time iterval; o the itegral form relatiohip i ot valid. Becaue the upper limit of the voltage fluctuatio periodicity i 5 mi, thi duratio would be the miimum period for the flicker pheomeo aalyi. The dicomfort produced by lumiace or light color fluctuatio a well a a flicker doe accumulatio are felt at the huma brai level, leadig to a itable viual perceptio, o ocoformig with the reality. Thee apect could favor accidet at work ad o the road traffic route a well. The ratioality of completig the idicator family for VSG reide i the eceity of their more complex characterizatio, o that to be able to etimate ythetic ad uequivocally the ifluece degree of the VSG o eitive itallatio ad equipmet. By aalyzig each equipmet family, uig at leat ome of the propoed idicator, it would be poible to highlight their eitivity at VSG. O thi bai, it ca be made a more accurate etimatio of the VSG coequece, by their depth ad duratio, which will allow a more accurate dimeioig of the parameter regardig the VSG effect limitatio.

16 46 Virgil Maier, Sori G. Pavel ad Horia G. Beleiu The equipmet ad coductor iulatio are treed owig to the voltage high value durig the STOV, but alo becaue of the voltage high icreaig gradiet. I additio, the reulted tree from the voltage icreae accelerate the iulatio agig, reducig the life operatig time of the electrical equipmet ad coductor. A more accurate etimatio of the STOV coequece may be made depedig their parameter ad duratio, which will allow a more appropriate choice of the meauremet take i order to limit the STOV effect. The aociatio betwee the kow idicator ad the ew defied oe lead to a complete idicator family for thee apect of the PQ. The practice of the additioal idicator ue, propoed for the voltage r.m.. value variatio, will be able to coecrate ome of them, the mot igificat oe followig to be ormalized. Eve if ot all idicator, which ow cotitute the voltage variatio idicator family will be rated, it mut ot be forget that ome of the idicator expreivity ca upport the highlightig of ome importat apect for the upplier ed-uer relatio. REFERENCES Arrillaga J., Wato N.R., Che S., Power Sytem Quality Aemet, Wiley, Chicheter, 300, 000. Beleiu H.G., Maier V., Mureşa P.D., Moldova H.A., Effect ad Method of Etimatig Power Quality Iue, Acta Electrotehica, 51, 5, Special Iue, Mediamira Sciece Publiher, Clu-Napoca (010). Bolle M.H.J., dertadig Power Quality Problem, Voltage Sag ad Iterruptio, IEEE ad Wiley Iterciece, Chicheter, 543, 000. Duga R.C., McGraagha M.F., Satoo S., Beaty H.W., Electrical Power Sytem Quality, Secod Editio, McGraw Hill Compaie, New York, 58, 003. Golovaov C., Albu M., Probleme modere de măurare î electroeergetică, Editura Tehică, Bucureşti, 800, 001. Hae P., Overvoltage Protectio of Low Voltage Sytem, d Editio (Tralatio from the Germa), the Ititutio of Electrical Egieer, Lodo, 358, 000. Leşe D., Maier V., Pavel S.G., Beleiu H. G., Voltage Quality Aalyi i a Network Poit of Iteret, Proc. of CIE 01 Cof., Jue 01, Oradea, Romaia, 107,,11. Maier V., Pavel S.G., Beleiu H.G., Buda C., Survey Regardig Additioal Idicator for Voltage Sag, Proc. of 13th Iterat. Cof. o Develop. a. Applicatio Syt., DAS 016, May, 016, Suceava, Romaia, iveritatea "Ştefa cel Mare" di Suceava, 016, Maier V., Pavel S.G., Beleiu H.G., Calitatea eergiei electrice,.t. PRESS, Clu- Napoca, 197, 01. Maier V., Pavel S.G., Beleiu H.G., Power Quality Cotrol i Low Voltage ad Medium Voltage Network, Eergetica, 1, 6-1 (003). Maier V., Pavel S.G., Beleiu H.G., Fărcaş V., Additioal Idicator for Short Time Overvoltage ad Voltage Impule, Proc. of Electrical a. Power Egg. Cof., EPE 016, October, Romaia, Techical iv. "Gheorghe Aachi" Jay, , 016.

17 Bul. It. Polit. Iaşi, Vol. 63 (67), Nr. 1, Maier V., Pavel S.G., Beleiu H.G., Fărcaş V., Ciorca C., Actual Apect of Flicker Pheomeo, The 9th Iterat. Symp. o Adv. Topic I Electrical Egg., ATEE 015, May 015, Bucharet, Romaia, Techical iv. Bucharet, 015, Praad Kodali V., Egieerig Electromagetic Compatibility; Priciple, Meauremet, Techologie ad Computer Model, ecod Editio, IEEE Pre, New York, 486, 001. Rya H.M., High Voltage Egieerig ad Tetig, d Editio, the Ititutio of Electrical Egieer, Lodo, 76, 001. * * * Voltage Characteritic i Public Ditributio Network, EN 50160, E, * * * Performace Stadard for the Power Ditributio Service, Cod ANRE , Bucureşti, ANRE, 007. * * * Electricity Supply Regulatio to Ed-uer, Moitorul Oficial al Româiei, 673, , Bucharet, 004. * * * Electromagetic Compatibility (EMC), Part 4: Tetig ad Meauremet Techique, Sectio 15: Flickermeter Fuctioal ad Deig Specificatio, IEC , * * * Electromagetic Compatibility (EMC), Part 4-30: Tetig ad Meauremet Techique-Power Quality Meauremet Method, IEC , 008. PROGRESE ÎN DEFINIREA NI SISTEM DE CALITATE A ENERGIEI ELECTRICE (Rezumat) Calitatea eergiei electrice ete apreciată pritr-u item de idicatori, alcătuit ditr-u aamblu de mărimi caracteritice, ditre care uele pot avea valori ormate. a ditre proprietăţile recuocute ale itemului de idicatori ete perfectibilitatea, apect uţiut pritr-o erie de articole recet publicate, de către autorii lucrării. Referitor la variaţiile valorii efective a teiuii reţelei, e propue evideţierea şi epararea variaţiilor de teiue datorate uor acţiui de iterveţie, efectuate au îregitrate la ivelul dipeceratelor. Î acet fel, rămâ de iterpretat mai puţie armoici ale variaţiilor lete de teiue. Recoiderarea relaţiei de calcul a fluctuaţiilor de teiue redă mai bie feomeul percepţiei vizuale. Difereţele obţiute pri utilizarea formulei propue vor iflueţa emificativ valorile idicatorilor de flicker. Mărimile caracteritice propue petru goluri şi uprateiui completează familia de idicatori ai variaţiilor valorii efective a teiuii,, urmâd ca î viitor ă fie ormaţi cei mai importaţi ditre aceştia.

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