SCADA & Digital Substation Elizabeth Johnson & Ritesh Bharat
GRID
Introduction to Digital Substations
INTRODUCTION The demand of electrical energy − led the Utilities to develop High and Ultra High Voltage networks − using AC and DC technology (1100 – 1200 kVAC ; 800 – 1100 kVDC) Control, Protection, Metering and all other IEDs − are using digital electronics − and should be able to communicate with IEC 61850 Standard Instrument Transformers are the link between the UHV line and the Protections and all secondary equipment ; They have to be designed for − higher insulation levels, − higher short circuit current capability, − higher bandwidth − extended dynamic range and high accuracy (primary current : 1A to 50 kA) New technologies are developed to meet new demanding requirements: − DIT (Digital Instrument Transformers; CT and VT), or “NCIT” − Digital Communications between « Process » apparatus and Bay/Station level − Control and Monitoring of active mechanisms (CB and DSC)
What is « Digital Substation » ? A global association of IEDs in the substation, including: Smart « intelligent » DCS (Digital Control System)
Smart Grid
New technologies of Instrument Transformers (NCITs) Merging--units for Sampled Values (CTs, VTs, NCITs) Merging Digital Controllers for CircuitCircuit-Breakers and Disconnectors On--line conditioning Monitoring (CB, DSC, GIS, TRANSFO) On
All these IEDs communicating together with digital standardized protocols defined in IEC 61850
Digital Instrument Transformers – How do they work?
Michael Faraday (1791－1867)
Optical CT Principle – Faraday Effect
Optical transparent medium Light polarization vector
I
Light propagation axis
H Current busbar
Rotation of the polarization plane of an optical wave, traveling in a magneto-optic material, under the influence of a magnetic field parallel to the direction of propagation of the optical wave
PRINCIPLE OF OPERATION
A light source sends light through a waveguide to a linear polarizer, then to a polarization splitter (creating two linearly polarized light waves), and finally to an optical phase modulator. This light is then sent from the control room to the sensor head by an optical fiber. The light passes through a quarter wave plate creating right and left hand circularly polarized light from the two linearly polarized light waves. The two light waves traverse the fiber sensing loop around the conductor, reflect off a mirror at the end of the fiber loop, and return along the same path. While encircling the conductor, the magnetic field induced by the current flowing in the conductor creates a differential optical phase shift between the two light waves due to the Faraday effect. The two optical waves travel back through the optical circuit and are finally routed to the optical detector where the electronics de-modulate the light waves to determine the phase shift. The phase shift between the two light waves is proportional to current and an analog or digital signal representing the current is provided by the electronics to the end user.
Why Optical CTs? Safety Intelligence and flexibility Availability Wire => Electric Power Optical Fiber => Information
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Safety
The optical CT does not “touch” the electrical power on the line. High voltage and ground are well separated with all dielectric insulation. The insulation contains no fuel.
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Intelligence and Flexibility
The optical sensor is fully self-diagnostic. Extremely high fidelity current measurements allow for improved system diagnostics Software configurability
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Availability Improved system availability is a consequence of safety and intelligence Unmatched reliability of outdoor equipment Electronics interchangeability + redundancy means no down time.
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NCIT Benefits DIGITAL − Intelligence for SMART GRIDs, smart redundancy, Ethernet connectivity (IEC 61850), self diagnostic,.. SAFETY − No HV coupling, no measurement service loss in event of a failure ENVIRONMENTAL − No oil, no SF6, no copper, zero footprint (for CTs), less mass ACCURACY − Wide dynamic range (extended range) frequency response DC to 10 kHz (includes the 100th harmonic) ADAPTABILITY − Easy installation and cabling, easy on-site testing, universal design software configurable, flexible form factor AVAILABILITY − Zero outdoor maintenance, electronics inter-changeability, HV passivity, short lead time, redundancy
Hardware modification in Analogue Modules” No need of Analogue CT & VT inputs
Digital CT & VT input board with IEC 61850-9-2
Analogue inputs are replaced by Ethernet connection 13
IEC 61850 Process Bus Digitalization and Transmission of CT and VT measurements multicast “Digital Standardized Interface” are a challenge But, It gives major benefits − − − − − −
cabling simplifications costs reductions introduction of NCIT measurement systems permanent self-monitoring safety etc.…
And Digital Control of Circuit-Breakers and Disconnectors
on
Types of Merging Units
AMU : Analog Merging Unit Interface with conventional instrument transformers
DMU : Digital Merging Unit Interface with CB / isolators / earth switches
IMU : Integrated Merging Unit Combination of AMU and DMU
NMU : Numerical Merging Unit Interface with digital instrument transformers
Typical Merging Unit
CT / VT Signals in the Protection
Comtrade file NCIT measurement In the protection
Comtrade file CIT measurement In the protection
Distance Protection P444 - results
With digital 9-2LE interface
Conventional analogue interface
Intelligent Primary Equipments
GIS Local Cubicle (LCC) CEVT-P/M CEVT-P/M
Analogue connections Synchro – 1pps
CEVT-P/M
PCtri-U
FO - Ethernet 100BaseFx
PCtri-I
N M U
IEC 61850-8-1
IEC 61850-9-2LE Or other protocol
MICOM P594
X
X
RECT-P/M IEC 61850-9-2LE
RECT-P/M RECT-P/M
Analogue
Or other protocol
connections
Digital/Analog Converter METER
PCtri-I : 3-phased current Primary Converter with Ethernet ports PCtri-U : 3-phased voltage Primary Converter with Ethernet ports
X
GRIDBOX – Controller and Monitoring for Circuit Breaker GRIDBOX can control and monitor standard alarms on breaker, transformer, disconnectors etc….
GRIDBOX – Controller and Monitoring for Circuit Breaker Main Features • Replace copper by optic fibber • Circuit breaker “full monitoring” • Trip Coil Supervision • Electrical/mechanical wear • Open/close travelling signature • Local static command of coils • Network synchronized time stamps of events • (GPS or IEEE1588) • IEC61850 communication Advantage • Decrease substation reconstruction cost • Increase communication reliability between the field equipment and control building • Benefit from accurate planning of maintenance/refurbishment/replacement • Obtain real time detection of equipment availability • Reduce command response time
DMC (Digital Motorized Control) for Disconnectors
The DMC device is installed inside motor operating mechanism applied to disconnect switches. The DMC device is designed to totally control the movement of the disconnect switch during opening and closing operations with an integrated electronic module The DMC allows the control mechanism (mechanical parts can be monitored both locally and remotely)
Features New operating mechanism equipped with DMC device features:
•Stainless steel box •Irreversible gearbox •Robust design to cope with adverse environmental conditions •Can be adjusted for any motor supply voltage •Less cabling and wiring •Reduced maintenance cost by preventive maintenance •Variable speed during the operations GRID •Modularity on the configuration to suit any type of installation
DMC Installation
DMC device is installed inside ALSTOM motor operating mechanism CMM series.
GRID
Monitoring Benefit DMC device permit to the user to:
• • • • • • • •
Archive curve which facilitates ageing and maintenance studies Evaluate the state of kinematic chain and live part position during the operation Continuously monitor the control circuit Control the real end open-close position of disconnector Obtain a precise indication of the operation times Record load curves in real time for a general evaluation before and after the maintenance and repairing Controls torque to operate the disconnector
GRID
Offer a flexible configuration based on the different disconnector type
Monitoring Specification DMC device monitors/controls following parameters as a function of position and time:
• • • • • • • •
Voltage Current Operating time Disconnector in motion/not in motion N° of operation cycle Max current reached Minimum voltage reached GRID Data are recorded in non-volatile memory and transferred via telecommunications serial RS 232.
Summary • • • • • • • • • • •
Motor power supply voltage : from 90Vdc – 250Vdc / 110-400 Vac 50/60Hz Remote control command power supply voltage: from 90Vdc-250Vdc / 90Vac-220Vac Variable speed configurable Mode of operation : Remote-Local-Manual Electrical connection on terminal board and connectors Electrical interlocking motor/manual operation Real time monitoring of the disconnector’s state Data recording for diagnostic Cams switch positioning system Serial output comunication RS 232 with local PC
GRID
Programmable positioning signal management with dedicated free contacts on terminal board
DMC Architecture with a “concentrator D-DSC”
3 x DMC A
B
3 x DMC C
A
B
C
D-DSC
I²CBus
Prot1
IEC 61850-8-1
Prot2
BCU
Met A
B
C
A
3 x DMC
B
Optical Fibers
C
3 x DMC
Prot A Met
DMC / IEC 61850-8-1
B 3 x DMC
C
System Architecture in Digital Substations
COSI
Digital Substation
SYSTEM ARCHITECTURE IEC 61850-8.1 & 9.2
GPS LOAD CENTERS IRIG-B
OPERATOR WORKSTATION
IEC 60870-5-101 Protections
IEC 60870-5-104
ENGINEERING WORKSTATION
REMOTE ACCESS
Ethernet
SNTP MODEM
RS232
MODEM
GATEWAY
Switch
Switch
ETHERNET OPTICAL LAN IEC61850-8.1 100MBps
IRIG-B
SNTP
Bay Computer
SNTP
Bay Computer
Bay Computer
Bay Computer
SNTP
Protections xn
IRIG-B
Protections xn
IEC 61850-8.1
Protections xn
MODBUS
IEC 60870-5-103
IEC 60870-5-103
IEC 60870-5-103
IEC 61850-8.1
CT/VT
IRIG-B
Protections xn
AVR
IRIG-B SNTP
AVR
TC TS TM 4-20mA
IEC 61850-9.2
GPS
IRIG-B
Switch 1PPS
1PPS
Switch
Merging Units
1PPS
IEC 61850-8.1
CIT = Conventional Instrument Transformers
NCIT = Non Conventional Instrument Transformers
System Architecture
XMU SELECTOR BB
DMC
DMC
DMC
DMC
DDSC
DDSC
DCCB
DCCB
PROT XMU DMC
DMC
BCU
PROT XMU DMC
DMC
BCU
Process Bus SV Process Bus GOOSE Station Bus
DCS PACIS – ETHERNET OPTICAL LAN – 100 Mbps – IEC 61850-8-1
COSI-NXCT Mounted on Live Tank CBs
National Grid, UK NXCT on a Siemens 420 kV live tank circuit breaker
Alstom GL317 with NCIT Enel Terna, Italy Candia S/S, 420 kV COSI-NXCT on VATECH live tank circuit breaker
COSI NXCT on CB Example of 400 kV OHL feeder 400kV OHL feeder bay
400kV OHL feeder bay with NXCT on LTCB
OHL feeder Comparison : footprint saving 15%
Conclusions NCITs & Process Bus offer huge potential advantages Cost and Space savings Interoperability : Digital Standard IEC 61850 Safety Reliability Availability Measurement Improvements
Thank You
www.alstom.com
