and Load Flow Control
The future of the rapidly changing global power distribution markets lies in the form of power grid operations.
Switching high currents, measures to be taken by power quality manage-ment and handling short circuits re-main the major tasks in this context.
New technologies, such as static and dynamic compensation equipment and network couplings based on power electronic components, are the logical choice to meet these challenges.
POWERCOMP are products and sys-tems that ensure high power quality of an industrial or public medium-volt-age supply grid. By utilizing systems for reactive power compensation that are tailored to meet customer re-quirements, the price of the power quantities delivered will be reduced.
Return of investment can often be achieved within less than two years.
In the event of significant load fluctu-ations, dynamic compensation sys-tems using thyristor valves or IGBT modules ensure a stable supply volt-age. Powerful filter circuit systems reduce effective harmonic currents of speed-controlled large drives, and thus, operating permits for the con-nection of such plants can be ob-tained. POWERCOMP systems are
modularly designed and can be used in the voltage range of 3 kV to 36 kV.
SIPLINK, the medium-voltage DC transmission system, allows econom-ical power exchange at the medium voltage level by using power elec-tronics. Power supply systems with differing parameters can thus be coupled, costs can be saved by opti-mizing power procurement, the load flow during power transmission is controlled and a constant supply of voltage is maintained through the provision of reactive power.
Innovative solutions for power supply
Most consumers don’t just draw ac-tive power from the grid but also re-active power which is somewhat er-ratically transmitted to the consumer.
For this reason, in their supply con-tracts, power supply companies de-fine the exact power factor as the ra-tio between active power to be trans-mitted and the apparent power. Any deviation is on account of the cus-tomer. This makes power quality management a very interesting topic.
Photo 4/37 2-MW SIPLINK system at the municipal utilities of Ulm in Germany
State-of-the art power electronics provide efficient and cost-effective options for optimizing power supply and power quality. Such applications
are gaining ground in the context of growing cost pressure and the wide-spread use of electronic modules and power electronics for automating and control tasks.
Thanks to the use of intelligent load flow controls, performance- and cost-optimized power procurement is now attainable. Subnetworks with deviat-ing parameters can also be con-nected, which means that their volt-age stability and quality can thus be positively influenced.
Applications in the field of power quality management initially require comprehensive measurements of power and harmonic ratios, which are taken using high-tech measuring in-struments. By means of a specially developed program, these data are evaluated in a network analysis that
simulates real conditions, taking nu-merous consumer and load require-ments into account.
This analysis helps to develop and implement the proper PQM solution even for highly complex and sensitive networks.
POWERCOMP
compensation systems for medium voltage
Compact, intelligent and expandable – this characterizes POCOS®, a sys-tem which is, above all, suitable for use in medium-voltage installations that require a compensation system for a certain technical process or for reasons of ambitious customer speci-fications. Extensive experience from use of this system the world over is continually being channeled into its further development.
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Input power supplied by the power supply company, to be paid by the customer
Input power from the tuning capacitor
Required apparent power
S Active power P
Reactive power Q
Fig. 4/37 Definition of electric power types – compensation
Photo 4/38 Outdoor installation
Photo 4/39 Compact compensation unit
As required, several units can be op-erated side by side. Choked or non-choked options are feasible. Despite the extremely compact design, a high compensation effect is achieved ow-ing to the use of vacuum switchgear, optimized capacitors and iron-core re-actors. Besides the basic model for indoor installation, systems for out-door installation are also available.
Compact compensation systems are not necessarily suited to every type of application. In some cases, it may be more reasonable to use conven-tional systems with capacitors or fil-ter circuits. For the primary industry (including paper, cement, steel, chemical and glass), this type of com-pensation system has been installed at every voltage level all over the
Wherever fast load changes result in a dynamic impact on the voltage at the point of connection, or wherever a highly sensitive voltage control is required, dynamic compensation sys-tems do the job. Their dynamic reac-tive-power compensation function can be combined with an active-power filtering function. Fast chang-ing load characteristics of arc fur-naces and mill trains affect the sys-tem voltage as much as, for example, the dynamic load characteristics in traction systems.
Long-standing experience and com-prehensive process knowledge about industrial power supply systems guarantee economical solutions that take customer needs into account.
For further information please con-tact:
[email protected] SIPLINK
Closed-loop controlled load flow for power systems with special re-quirements
With SIPLINK (Siemens Multifunc-tional Power Link), Siemens has de-veloped a technology for medium-voltage direct current transmission that – depending on the application and configuration of an existing sup-ply system – can be utilized by power supply companies and industrial plant operators alike to make tremendous savings in terms of costs of invest-ment, operation and total plant serv-ice life.
SIPLINK controls the load flow during power transmission and ensures opti-mal voltage stability by a controlled output of reactive power.
In order to do so, SIPLINK uses tech-nology that is based on
self-commu-cally isolated. In this case, the con-nected networks may even feature different voltage levels, neutral point connections, frequencies and phase angles.
The SIPLINK can also be used to sup-ply a separate network without a power generating set of its own, in particular if network parameters that differ from the distribution system are required. Typical examples are test bays (for 60 Hz or surge voltage generation), or shipyards and connec-tion points in harbors for the supply of on-board networks of ships. Indi-vidual plant sections with different requirements to power quality and safety of supply can also be operated isolated from the general power sup-ply using SIPLINK.
For further information please contact:
Photo 4/40 SIPLINK ship
Photo 4/41 Transformer/container model