How do I Implement Hybrid Solutions for LV Dynamic Power Factor Correction

Transcription

1 How do I Implement Hybrid Solutions for LV Dynamic Power Factor Correction + and VarSet Application Note: v1.0 (September 2017)

2 Legal Information The Schneider Electric brand and any registered trademarks of Schneider Electric Industries SAS referred to in this guide are the sole property of Schneider Electric SA and its subsidiaries. They may not be used for any purpose without the owner's permission, given in writing. This guide and its content are protected, within the meaning of the French intellectual property code (Code de la propriété intellectuelle français, referred to hereafter as "the Code"), under the laws of copyright covering texts, drawings and models, as well as by trademark law. You agree not to reproduce, other than for your own personal, noncommercial use as defined in the Code, all or part of this guide on any medium whatsoever without Schneider Electric s permission, given in writing. You also agree not to establish any hypertext links to this guide or its content. Schneider Electric does not grant any right or license for the personal and noncommercial use of the guide or its content, except for a non-exclusive license to consult it on an "as is" basis, at your own risk. All other rights are reserved. Electrical equipment should be installed, operated, serviced and maintained only by qualified personnel. No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this material. As standards, specifications and designs change from time to time, please ask for confirmation of the information given in this publication.

3 Safety Information Important information Read these instructions carefully and look at the equipment to become familiar with the device before trying to install, operate, service or maintain it. The following special messages may appear throughout this manual or on the equipment to warn of potential hazards or to call attention to information that clarifies or simplifies a procedure. The addition of either symbol to a Danger or Warning safety label indicates that an electrical hazard exists which will result in personal injury if the instructions are not followed. This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death. DANGER DANGER indicates a hazardous situation which, if not avoided, will result in death or serious injury. WARNING WARNING indicates a hazardous situation which, if not avoided, could result in death or serious injury. CAUTION CAUTION indicates a hazardous situation which, if not avoided, could result in minor or moderate injury. NOTICE NOTICE is used to address practices not related to physical injury. Please note Electrical equipment should be installed, operated, serviced and maintained only by qualified personnel. No responsibility is assumed by Schneider Electric for any consequences arising out of the use of this material. A qualified person is one who has skills and knowledge related to the construction, installation, and operation of electrical equipment and has received safety training to recognize and avoid the hazards involved.

4 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. Contents Legal Information... 2 Safety Information... 3 Important information... 3 Please note... 3 Contents... 4 Document Summary... 5 Document Scope... 5 Supporting Documentation... 5 Terms and Definitions Conventional LV Power Factor Correction Fixed Power Factor Correction Automatic Power Factor Correction Dynamic LV Power Factor Correction PFV PCS VarSet Capacitor Banks Operating Principle Solution Architecture and Recommendations Hybrid VAR Compensation in Low Voltage System Fix Capacitor and PFV Automatic PFC Bank and PFV Automatic PFC Bank with PCS+ and PFV Active Filter and Automatic Compensation Bank in LV System Automatic PFC Bank with PCS Use of Summation CT and shorting terminals Page 4 of Schneider Electric. All rights reserved.

5 Document Summary Hybrid Var Compensator (HVC) The Hybrid VAR Compensator is ideally suited for ultra fast reactive power compensation in many low voltage distribution networks containing highly transient loads where conventional systems are not suitable (too low). The HVC employs a fixed or automatic capacitor bank to provide reactive power at all time, while PFV+ adjusts the output to meet system reactive power requirement in timely manner. PFV+ provides dynamic VAR injection to meet reactive power requirement within 1/4 cycle, reduce voltage sags created by inductive load switching, welding operation, etc. HVC can be also proposed with PCS + for harmonic mitigation if non-linear loads are installed and create some distortion. HVC configurations involve special requirement for CT sensing to work correctly. Installation with Active filter & Automatic PFC bank Document Scope Supporting Documentation Paragraph 3.1 of this document gives a description of architectures validated for Hybrid reactive compensation and requirement for the CT position. On large installations, very often there is a need to reduce the harmonic pollution and improve the power factor. Paragraph 3.2 on the document present architecture diagrams with Active Filter & Automatic caps bank. In these installations, there are also some requirements for CT location which need to be followed. This guide is entented for Application Engineers and contractors. + brochure: Reference AMTED109015EN VarSet catalogue: Reference PFCED310004EN 2017 Schneider Electric. All rights reserved. Page 5 of 17

6 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. Terms and Definitions Term HVC ROI PFC Description Hybrid Var Compensation Return On Investment Power Factor Correction Page 6 of Schneider Electric. All rights reserved.

7 1 Conventional LV Power Factor Correction The conventional solution for power factor correction is the use of capacitor banks. These capacitor banks are of two main types: The Fixed capacitor banks The Automatic capacitor banks 1.1 Fixed Power Factor Correction The Fixed capacitor bank is made of capacitor units permanently connected to the system as one sole system. It can only be fully On or Off with no other possible adjustment of the correction done. Example of single line diagram for a fixed capacitor bank: 1.2 Automatic Power Factor Correction The Automatic capacitor bank is made of capacitor units organized in Steps. The steps are controlled by a power factor controller and operated by switching devices (contactor / circuit-breaker ). This allows adjustment, step by step, of the power factor correction done to the system. Example of single line diagram for an automatic capacitor bank: 2017 Schneider Electric. All rights reserved. Page 7 of 17

8 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. 2 Dynamic LV Power Factor Correction Our dynamic solution for low voltage power factor correction solution is using Schneider Electric standard equipment: PFV+ electronic var compensator, PCS+ active harmonic filter and VarSet low voltage capacitor banks. 2.1 PFV+ PFV+ is part of Schneider Electric range of active filters. PFV+ is a very simple and effective means to eliminate leading or lagging power factor, reduce voltage fluctuations, enhance equipment operating life, and improve system power capacity. PFV+ offers many features in one package that others require multiple models to accomplish. Power Factor correction with PFV+ is worry-free and without the risk of resonance. Refer to + brochure (Ref: AMTED109015EN) 2.2 PCS+ PCS+ is part of Schneider Electric range of active filters. PCS+ is a flexible, high performance, cost-effective solution for stabilizing networks by providing harmonic mitigation, power factor correction and load balancing. PCS+ is a complete solution for harmonic filtering that meets every harmonic standard around the world. Refer to + brochure (Ref: AMTED109015EN) 2.3 VarSet Capacitor Banks VarSet is Schneider Electric range of low voltage capacitor banks. VarSet low voltage capacitor bank is a complete range of high quality power factor correction solutions engineered to compensate reactive power. These are highperforming, cost effective & energy management ready solutions that can immediately boost your facility s energy efficiency and productivity. Thanks to VarSet, your power factor is maintained at an ideal level for optimum power system efficiency and cost reduction Page 8 of Schneider Electric. All rights reserved.

9 VarSet power factor correction range helps lower operating and capital costs, providing quick ROI: Reduce capital expenses by up to 30% Reduce reactive energy billing penalties & lower operating expenses by up to 10% Reduce energy losses by up to 30% Improve power system & equipment reliability by up to 18% Refer to VarSet catalogue (Ref: PFCED310004EN) 2.4 Operating Principle The principle is the following: 1. The capacitor bank injects permanently a fixed amount of reactive power (capacitive). 2. The dynamic var compensation equipment makes real time adjustment injecting capacitive or inductive reactive power. 3. The result is a real-time compensation Example: In red: kvar permanently injected by fixed VarSet capacitor bank, In green: leading or lagging kvar generated by the equipment. In blue: kvar injected by the dynamic solution. This line is the sum of the 2 previous lines. It is the result of the permanent injection of the capacitor bank + the real time +/- kvar adjustment (capacitive or inductive) by the dynamic var compensation equipment Schneider Electric. All rights reserved. Page 9 of 17

10 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. 3 Solution Architecture and Recommendations 3.1 Hybrid VAR Compensation in Low Voltage System Fix Capacitor and PFV+ Principle diagram: PFV+ Qc Realization diagram: PFV+ Qc PFV+ CT s sense I source. 2 CTs are required. (If there are single phase loads connected between Ph and Neutral, then 3 CTs are required). Follow the CTs polarity as per the arrow. Generally, PFV+ is rated at the same KVAR as the fix capacitor value (Qc), so this diagram allow fast reactive compensation, from Q = 0 (in this situation, PFV+ provides - Qc), up to Q = 2*Qc (in this situation, PFV+ provides +Qc) Page 10 of Schneider Electric. All rights reserved.

11 Hybrid VAR Compensator Qc fix capacitor (kvar) (KVAR) Accusine PFV+ ( kvar) Net system (kvar) HVC operation example: 300 kvar Fixed Detuned Passive Amp PFV+ PFV+ can be a single unit or several units operating in parallel to increase rating. Q PFV+ max = 2500KVAR (10 x 300A-480V) Note Contact Competency Center if more than 10 units are required Automatic PFC Bank and PFV+ Principle diagram: PFV+ Automatic PFC bank 2017 Schneider Electric. All rights reserved. Page 11 of 17

12 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. Realization diagram: x1 x1 PFV+ Automatic PFC bank This diagram requires 4 CTs, - 2 CTs for PFV+ located on source. - 2 CTs for Automatic PFC bank, 1 CT located on source and 1 CT located on PFV+ connection (connected in parallel of the source CT but in reverse position). Follow the CTs polarity as per the arrow. Sizing of the automatic PFC bank and PFV+ depends on the load reactive variation. Automatic PFC bank will be rated to compensate slow reactive variation PFV+ will be rated to compensate fast reactive variation This is recommended to use a PFC bank with all steps at same size to have a correct balancing between all steps. The switching time of the PFC controller used in automatic PFC bank (10s per default) will be increase to a value compatible with both, - life duration of contactors & caps (around switching s), - accuracy and speed expected on reactive power regulation. To have a switching time no to important with a correct life duration of Automatic PFC bank (> 7 years), it is recommended to increase number of steps. PFV+ can be a single unit or several units (up to 10) operating in parallel to increase rating up to 2500KVAR (eg 10 x 300A at 480V). Note Contact Competency Center if more than 10 units are required Page 12 of Schneider Electric. All rights reserved.

13 Automatic PFC Bank with PCS+ and PFV+ This solution allows Hybrid Var Compensation and Harmonics mitigation/ Principle Diagram PFV+ Automatic PFC bank Accusine PCS+ Realization Diagram x1 x1 PFV+ Automatic PFC bank PCS+ PCS+ or PFV+ can be single unit or parallel units This diagram require 8 CTs: - 2 CTs for PFV+ located on source, - 2 CT s for Automatic PFC bank, 1 located on the source and 1 on PFV+ connection (connected in parallel of the source CT but in reverse position) - 4 CT s for PCS+, 2 located on the source and 2 on Automatic PFC bank connection (connected in parallel of the source CT but in reverse position) Follow the CTs polarity as per the arrow In this solution, we recommend to use Automatic PFC bank with Detuned reactor (3.8 th harmonic order preferred). So if PCS+ units are temporarily stopped, PFC bank can handle a temporary increase of THDU up to 8%. PFV+ or PCS+ can be a single unit or several units (up to 10 units for each) operating in parallel. Note Contact Competency Center if more than 10 units are required 2017 Schneider Electric. All rights reserved. Page 13 of 17

14 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. 3.2 Active Filter and Automatic Compensation Bank in LV System Automatic PFC Bank with PCS+ x1 Automatic PFC bank PCS+ Such configuration with a capacitor bank (Automatic or Fix) connected on the same distribution busbar than PCS doesn t work. Capacitor bank is connected between CT sensor and the load and in this configuration, there is some instability. Two Solutions are possible to avoid such issues: 1- move cap downstream to CTs x1 Automatic PFC bank PCS+ CT s don t see anymore the capacitor bank current and all is working fine. PCS + need to be set for harmonic compensation only. 2 add auxiliaries CTs in the capacitor branch to substract the Caps current to CT s it gives this realization diagram below Page 14 of Schneider Electric. All rights reserved.

15 x1 Automatic PFC bank PCS+ Aux. CTs are installed on PFC bank branch in opposite side so current absorb by the PFC bank is substract to the Grid current sense by PCS+. Aux CT ratio should be the same as CT s. PCS + need to be set for harmonic compensation only The impact on the principle diagram can be seen below: Use of Summation CT and shorting terminals Summation CTs are mandatory when several CTs are connected in parallel and when the sum of secondary current can exceed the maximum value accepted by the burden resistor. Example: 2 sources transformer in parallel (for power increase) 1000KVA each with CT 2000/5A Without summation CT: the 2 CTs are in parallel, when the 2 transformers are at full load the secondary current will be: Is = 1500 x (5/2000) x 2 =7,5A. CT burden resistors will burnt (they are size for 5A permanently) With summation CT 5+5/5A. See diagram below 2017 Schneider Electric. All rights reserved. Page 15 of 17

16 How do I implement hybrid solutions for LV dynamic PF correction Błąd! Użyj karty Narzędzia główne, aby zastosować Titre 1 do tekstu, który ma się tutaj pojawić. PCS+ The 2 set of CTs are connected to the summation CT 5+5/5. This summation CT introduces an additionnal ratio of 2. When the 2 transformers are at full load the secondary current will be : Is = 1500x(5/2000)x 2/2 =3,75A. The CTs ratio to be entered in personalization is the double of the main CT: 2x(1500/5) = 3000/5A Another solution consists in increasing the ratio of the main CTs. With the same example. - we can use 4000/5 CTs and then summation CT is no more necessary, - we can also use 2000/1 CTs. The current with the 2 Cts in parallel will reach 1,5A: this is compatible with the burden resistor ( which accept up to 5Amps) If a CT 5+5+5/5A is used the additional ratio is 3. If some inputs are not used this is recommended to installed a jumper installed between P1 and P2 terminal to avoid measurement error. All CTs connected in parallel should be identical ( same model, same ratio,.;) All CTs connected to a summation CT need to have the same ratio: per ex, you cannot put in parallel a CT 2000/1 and 1000/1. PCS + CT terminal are design to connected 2 CT input. When more than 2 CT perphase occurs, intermediary shorting CT terminal block is required. Page 16 of Schneider Electric. All rights reserved.

17 Schneider Electric 35 rue Joseph Monier Rueil Malmaison France As standards, specifications, and designs change from time to time, please ask for confirmation of the information given in this publication. Copyright 2017 Schneider Electric. All rights reserved. 09/2017