284:
of reactive power with self-regulation (the supply fortuitously increases with higher load) being the secondary consideration; The voltage across a series capacitor is typically low (within the regulation range of the network, few percent of the rated voltage), so its construction is relatively low-cost. However, in the case of a short on the load side, the capacitor will be briefly exposed to the full line voltage, thus protection circuits are provisioned, usually involving
276:
are used in power systems since the 1910s and are popular due to low cost and relative ease of deployment. The amount of reactive power supplied by a shunt capacitor is proportional to the square of the line voltage, so the capacitor contributes less under low-voltage conditions (frequently caused by
323:
The passive compensation devices can be permanently attached, or are switched (connected and disconnected) either manually, using a timer, or automatically based on sensor data. The active devices are by nature self-adjusting. The tap-changing transformers with under-load tap-changing (ULTC) feature
283:
are used to compensate for the inductive reactance of the loaded overhead power lines. These devices, connected in series to the power conductors are typically used to lower the reactive power losses and to increase the amount of active power that can be transmitted through the line, with the supply
347:
is that as the load increases, the lines start consuming an increasing amount of reactive power that needs to be replaced. Thus a large transmission system requires reactive power reserves just like it needs
343:) since a single failure of a generator or a transmission line (that has to be planned for) has the potential to immediately increase the load on some of the remaining transmission lines. The nature of
324:
can be used to control the voltage directly. The operation of all tap-changing transformers in the system needs to be synchronized between the transformers and with the application of shunt capacitors.
97:
the power network equipment is designed for a narrow voltage range, so is the power consuming equipment on the customer side. Operation outside of this range will cause the equipment to fail;
218:
In a typical electrical grid, the basics of the voltage control are provided by the synchronous generators. These generators are equipped with automatic voltage regulators that adjust the
69:
will be primarily used to designate this essentially single activity, as suggested by Kirby & Hirst (1997). Voltage control does not include reactive power injections to dampen the
77:. The transmission of reactive power is limited by its nature, so the voltage control is provided through pieces of equipment distributed throughout the power grid, unlike the
327:
Due to the localized nature of reactive power balance, the standard approach is to manage the reactive power locally (decentralized method). The proliferation of
352:. Since the reactive power does not travel over the wires as well as the real power, there is an incentive to concentrate its production close to the load.
100:
reactive power causes heating in the generators and the transmission lines, thermal limits will require restricting the production and the flow of real (
206:
usually absorb the reactive power, with the power factor for typical appliances ranging from 0.65 (household equipment with electrical motors, like a
353:
752:
716:
142:
798:
256:). A shunt reactor is typically connected to an end of a long transmission line or a weak system to prevent overvoltage under light load (
277:
the lack of reactive power). This is a serious drawback, as the supply of reactive power by a capacitor drops when it is most needed;
444:
Siva Kumar, C. H.; Mallesham, G. (2020). "Implementation of ANN-Based UPQC to
Improve Power Quality of Hybrid Green Energy System".
107:
injection of reactive power into transmission lines causes losses that waste power, forcing an increase in power supplied by the
309:
691:
264:
50:
735:
373:
175:
will provide reactive power if overexcited and absorb it if underexcited, subject to the limits of the generator
357:
74:
197:
360:, so the trend is to push the problem onto the customer and require the load to operate with a near-unity
305:
116:
301:
219:
172:
124:
133:
and systems that exhibit large changes in voltage when the reactive power conditions change are called
70:
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245:
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108:
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58:
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54:
32:
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748:
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467:
349:
211:
78:
46:
28:
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339:
The system should be capable of providing additional amounts of reactive power very quickly (
777:
451:
176:
707:. In Naser Mahdavi Tabatabaei; Ali Jafari Aghbolaghi; Nicu Bizon; Frede Blaabjerg (eds.).
700:
257:
207:
203:
193:
200:
are capacitive, so they are loaded below the surge impedance and provide reactive power.
781:
82:
62:
57:
on these networks. Both aspects of this activity are intertwined (voltage change in an
168:
Electric grid equipment units typically either supply or consume the reactive power:
792:
253:
361:
196:
of the line, the lines start consuming an increasing amount of reactive power. The
154:
101:
241:
passive (either permanently connected or switched) sinks of reactive power (e.g.,
770:
Khan, Baseem (2022). "Reactive power management in active distribution network".
742:
455:
316:
222:
field keeping the voltage at the generator's terminals within the target range.
182:
120:
17:
762:
726:
93:
Kirby & Hirst indicate three reasons behind the need for voltage control:
471:
463:
328:
285:
267:
192:
will provide reactive power at low load, but as the load increases past the
162:
161:-like) and produce reactive energy if they have a leading power factor (are
130:
709:
Reactive Power
Control in AC Power Systems: Fundamentals and Current Issues
292:
158:
115:
Use of specialized voltage control devices in the grid also improves the
127:(that are caused by generators sourcing or sinking the reactive power).
249:
705:"Reactive Power Role and Its Controllability in AC Power Systems"
447:
Energy
Systems, Drives and Automations: Proceedings of ESDA 2019
248:
that are similar to transformers in construction, with a single
331:
might make the flexible centralized approach more economical.
289:
73:; these are a part of a separate ancillary service, so-called
61:(AC) network is effected through production or absorption of
188:
Power lines will either absorb or provide reactive power:
137:, while the ones that have relatively smaller changes are
680:
Ancillary service details: Voltage control (ORNL/CON-453)
391:
389:
536:
534:
497:
495:
493:
356:
takes this area of the power grid out of hands of the
312:
that can be either sources or sinks of reactive power;
648:
153:
Devices absorb reactive energy if they have lagging
263:passive sources of reactive power (e. g., shunt or
31:. For general aspects of voltage control, see
141:(numerically, the strength is expressed as a
8:
747:. McGraw-Hill Education. pp. 627–687.
149:Absorption and production of reactive power
660:
636:
407:
395:
145:that is higher for the stronger systems).
81:that is based on maintaining the overall
677:Kirby, Brendan J.; Hirst, Eric (1997).
385:
354:Restructuring of electric power systems
773:Active Electrical Distribution Network
612:
600:
588:
576:
564:
552:
540:
525:
513:
501:
484:
419:
210:) to 1.0 (purely resistive loads like
185:will always absorb the reactive power.
7:
736:"Reactive Power and Voltage Control"
624:
431:
119:by reducing the fluctuations of the
65:), so within this article the term
782:10.1016/B978-0-323-85169-5.00005-8
744:Power System Stability and Control
734:Kundur, Prabha (22 January 1994).
25:
649:Ibrahimzadeh & Blaabjerg 2017
49:that enables reliability of the
450:. Springer Nature. p. 16.
315:regulating transformers (e.g.,
310:static synchronous compensators
776:. Elsevier. pp. 287–301.
711:. Springer. pp. 117–136.
1:
692:Oak Ridge National Laboratory
799:Electric power transmission
456:10.1007/978-981-15-5089-8_2
350:reserves for the real power
300:active compensators (e.g.,
227:reactive power compensation
815:
26:
374:Active Network Management
43:reactive power management
27:This article is about an
358:integrated power utility
89:Need for voltage control
75:system stability service
699:Ibrahimzadeh, Esmaeil;
335:Reactive power reserves
306:static var compensators
225:The task of additional
198:underground power lines
661:Kirby & Hirst 1997
637:Kirby & Hirst 1997
408:Kirby & Hirst 1997
396:Kirby & Hirst 1997
302:synchronous condensers
117:power system stability
173:Synchronous generator
125:synchronous generator
51:transmission networks
45:are two facets of an
688:Oak Ridge, Tennessee
345:overhead power lines
235:compensating devices
231:voltage compensation
190:overhead power lines
83:active power balance
53:and facilitates the
627:, pp. 292–293.
591:, pp. 629–638.
579:, pp. 635–637.
567:, pp. 633–634.
516:, pp. 631–632.
487:, pp. 627–628.
341:dynamic requirement
143:short circuit ratio
59:alternating current
212:incandescent lamps
55:electricity market
33:Voltage regulation
754:978-0-07-035958-1
718:978-3-319-51118-4
410:, pp. 1, 15.
281:series capacitors
233:) is assigned to
79:frequency control
71:grid oscillations
47:ancillary service
29:ancillary service
16:(Redirected from
806:
785:
766:
740:
730:
703:(5 April 2017).
701:Blaabjerg, Frede
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274:shunt capacitors
204:Electrical loads
177:capability curve
21:
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295:, and switches;
258:Ferranti effect
229:(also known as
208:washing machine
194:surge impedance
151:
91:
85:in the system.
67:voltage control
39:Voltage control
36:
23:
22:
18:Voltage control
15:
12:
11:
5:
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790:
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731:
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672:
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666:
665:
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651:, p. 119.
641:
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615:, p. 633.
605:
603:, p. 678.
593:
581:
569:
557:
555:, p. 631.
545:
543:, p. 629.
530:
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518:
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489:
477:
436:
434:, p. 295.
424:
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412:
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319:transformers).
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261:
216:
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63:reactive power
24:
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34:
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19:
772:
743:
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679:
663:, p. 2.
656:
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620:
608:
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584:
572:
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403:
398:, p. 1.
362:power factor
340:
338:
326:
322:
317:tap-changing
280:
273:
234:
230:
226:
224:
217:
183:Transformers
167:
155:power factor
152:
138:
135:weak systems
134:
129:
114:
92:
66:
42:
38:
37:
613:Kundur 1994
601:Kundur 1994
589:Kundur 1994
577:Kundur 1994
565:Kundur 1994
553:Kundur 1994
541:Kundur 1994
526:Kundur 1994
514:Kundur 1994
502:Kundur 1994
485:Kundur 1994
420:Kundur 1994
131:Power buses
121:rotor angle
109:prime mover
763:1054007373
727:1005810845
380:References
329:microgrids
286:spark gaps
268:capacitors
220:excitation
625:Khan 2022
472:1876-1100
464:1876-1119
432:Khan 2022
293:varistors
252:and iron
163:capacitor
793:Category
368:See also
246:reactors
165:-like).
159:inductor
104:) power;
671:Sources
250:winding
761:
751:
725:
715:
470:
462:
265:series
139:strong
102:active
739:(PDF)
684:(PDF)
460:eISSN
243:shunt
157:(are
123:of a
759:OCLC
749:ISBN
723:OCLC
713:ISBN
468:ISSN
254:core
41:and
778:doi
452:doi
290:ZnO
270:).
795::
757:.
741:.
721:.
690::
686:.
533:^
492:^
466:.
458:.
388:^
364:.
308:,
304:,
288:,
260:);
237::
214:).
784:.
780::
765:.
729:.
694:.
474:.
454::
179:.
111:.
35:.
20:)
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