Voltage Management of Low voltage (LV) BusbarsPlenary session B – Low voltage operation

Dan RandlesQuality of Supply and Technical Manager/LCNF Tier 1 Manager

LCNF ConferenceOctober 2012

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Aims and Objectives

Aim is to trial solutions with potential to help voltage management on LV networks and to provide operators with understanding of the potential for alternative methods to cope with the changing nature of demands• ability to effectively manage voltages in real-time in a safe and

economical manner will be assessed

• effectiveness of devices to correct power factor will be assessed

• Issues including phase imbalance and power quality to be assessed where appropriate supported by simulations

30 month project started in April 2011 costing £0.5M

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Scope

6 sites selected for trials (11kV or 6.6kV)

Simulations used to explore numerous scenarios

PV clusters or high load areas (or both)

LV network monitoring deployed (Incl. PQAs)

Dunton Green Edge Green Greenside

Howard St Landgate Leicester

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Network Monitoring (LVNS)

Scope of the deployment• 200 x 11kV or 6.6kV to 415V

distribution substations• Over 1000 LV feeders• Sites comprise indoor and

outdoor, mostly ground mounted with small number of pole mounted transformers

Analogues to be captured• RMS voltages and currents• Real and reactive power• 3ø + neutral • Temperature (Ambient, Tx)• Real-time (1 minute

averages!)• Harmonics (not real time)

Metrology and Communications

(V, I, Q, P, H, Temp)

GPRS/3GPrivate APN

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Trials

Three techniques were explored through field trials

Numerous more will be looked at through simulations

Field trials:• Substation (ie busbar) voltage regulation via OLTC

distribution transformer• Harmonic filtering, power factor correction and phase

balancing via active filter • In-line (ie LV feeder) voltage regulation via power

optimizer

Field trials commenced in August 2012 and will continue for a period of 12 months

Too early in the trial stage to assess results but lots of valuable practical learning already obtained

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Voltage Management – Active Harmonic Filters

As well as harmonic filtering the AHF provides load balancing and power factor correction

Technical details:• Active Filter Type PQFS – M10 amp• Voltage (V): 420V• Frequency (Hz): 50• Total Current (A): 100• Total Power (kVA): 71• IP Rating - IP30• Ambient Temperature -10oC/+40oC• Dimensions: W585 x D310 x H685

mm

ENW have installed the AHF at two locations in Manchester; 1 indoor and 1 outdoor

Full harmonic studies have been completed prior to the installation to ascertain background harmonic levels

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Voltage Management – Power Perfector (PP+)

320kVA rating

Voltage optimiser has the capability to adjust target volts

AVC available taps (+4%, 0%, -4%, -8%, -12%) and (+2.7%, 0%, -2.7%, -5.4%, -8.1%)

Operating temperature range: - 10oC/+50oC

Installed by-pass arrangement for trial

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Voltage Management – On load Tap changing Distribution Transformer

x2 OLTC distribution transformers from Reinhausen of Germany (MR)

Technical details for the OLTC:• 500kVA rating• x1 unit at 11kV and x1 unit at 6.6kV• Tapping range - 8% to + 8% in 8

steps of 2%• Utilises the MR OLITAP mechanical

tap changer• Tap changer incorporated within a

‘modified’ UK standard EFACEC Tx• Voltage control relay via

TAPCON230 with DNP3

Delivered in September 2012 installation scheduled for December

Fundamentals providing design and installation support for the AVC equipment

AV

C

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LV Feeder Voltage Control

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Lessons learnt

Approvals, policies and authorisations

Customer impact must be minimised particularly noise and interruptions

True partnering approach with all project stakeholders

Academic support crucial to help make sense of results

Site surveys essential to avoid problems during installation

Installation quality including anti tamper/vandal

Network monitoring key to understanding the outcomes

Large volumes of data being generated which needs managing – requires new tools/systems

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Network Modelling

Topology Information MPAN

InformationConductorInformation

Relationship MPAN-Profile

Class

Profiles Class (half hourly

profile)

ReconnectionModel

OpenDSS Representation

Power Flow Simulation

From GIS

From other Database

Automatic Process

Validate

Extract

Analyse

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Future solutions

The adoption at scale of low carbon technologies will have a significant impact on LV networks

• Voltage rise/drop

• Congestion/overload of assets

Monitoring is key to firstly understanding the capabilities of LV networks both now and in the future and secondly facilitating smart operation

Appears likely that active means of controlling voltages and loadings in LV networks will be implemented in the future

Significant change in operation and planning procedures for network operators

These techniques are introducing complexity into networks which are inherently simple – this represents a challenge to operators

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Thank you

Any questions…?