Protection History

Author: Walter Schossig, Germany

On the Way to IEDs

The huge step from protection relays to IEDs (Intelligent Electronic Devices) was described in the last issue- the combination of protection and control in a single device. Digital relays became widely accepted since 1990. Mechanical and especially static relays became less attractive. At the turn of millennium more than 100 000 digital relays were installed in Germany.  A lot of substations have been retrofitted with digital protection. This was because of the clear advantages:

  • More functionalities for less money
  • Less wiring, less space, less effort for documentation
  • Integrated self-supervision reduces demand for testing – the way to event oriented maintenance
  • Integrated fault locator and disturbance recording improve fault detection and reliability of the grid
  • Remote control and remote diagnosis makes the visit of outlying substations obsolete

SIEMENS introduced SIPROTEC 4 in 1998.  Multifunctional devices such as 7SJ61 (Figure 3), 7SJ62 and 7J63 (Figure 1) became quite popular. Additional devices have been 7RW600 (decoupling and load shedding), busbar protection 7SS52 and line differential 7SD52 (later 7SD600). 7SJ61 contained overcurrent protection, motor protection and control capabilities. 7SJ62 came in addition with directional element, voltage and frequency protection as well additional automation functionalities. For the 7SJ63 a single line display was available and direct motor control as well. SCADA connection was realized with IEC 60870-5-103 or Profibus at this time. When the decentralized busbar and breaker failure protection 7SS52 came out it consisted of central unit (7SS520) and field units (7SS521). Operating times of less than 15 ms have been achieved.

Distance protection 7SA6 of V4 series and generator protection 7UM6 was released in 2000. In 2010, SIPROTEC 5 was presented for the first time. The different devices as line protection (7SA84, 7SA86, 7SA87, 7SD84, 7SD86, 7SD87, 7SL86, 7SL87, 7VK87, 7SJ85); transformer protection (7UT85, 7UT86, 7UT87) and busbar protection (7SS85) are available since March 2012. Additionally fault recorder KE85 and bay controllers 6MD85 and 6MD86 came out.
With directional overcurrent protection 7SJ66 containing integrated protection for infeed and 7UT82 for two winding transformers as well as arc protection for SIPROTEC 5 and capacitance protection 7SR191 the product line was completed. A protection concept with SIPROTEC 5 for three winding transformers is shown in Figure 2. Table 1 gives an overview about the hardware used at SIEMENS from 1986 until 2004.

Reyrolle in UK designed and launched a new range of multi-function overcurrent relays named Argus in 1994. These relays used microprocessor technology which enabled more features, such as communications, data storage and alphanumeric display to be provided. The relay incorporated an event recorder that time and date stamped the last 100 events and as a consequence was named Argus- a mythical creature with 100 eyes; Malcolm Wheatley, an engineer in protection R&D suggested the name. The Argus family developed into six variants. In the latest version the event log can hold 500 events. The world’s first adaptive relay using neural networks was presented by Reyrolle in 1997. The first dual directional numeric multi-function overcurrent relay ARGUS 2 is shown in Figure 4.

The first numeric integrated Transformer Differential Protection (Duobias) was presented by Reyrolle in 1989 already. 
Talking about ALSTOM, the Modulex3 line should be mentioned (Figure 5).

Between 1995 and 2010 more than 30000 MX3 units are sold in the world. Typical examples:

  • 1992 MX3IPG1A  Integrated protection for Generator
  • 1995  MV3AM Multifunctional Relay
  • 2005 MX3EG1A  Automatic synchronizer and MX3EG2B  Synchronization control
  • 2005 MX3DK5600, DK5740 Interface Protection
  • 2009 MX3CEI016, New Interface Protocol

Line differential LFCB was released already in 1986. With the company name AREVA MiCOM P54x was presented in 1999 as well as the distance protection MiCOM P442 and P447.  Of the MiCOM P14x series over 100000 units are in use (since 1999), the new series P40 and P60 Agile are available since 2012.
ABBs IED 670 series was presented in 2006. These devices summarize several functions combined with high flexibility to be used in transmission and distribution. With the tool PCM 600 setup and adaptation is possible.

  • Bay controller REC670
  • Busbar protection REB670
  • Line differential RED670
  • Distance REL670
  • Transformer differential RET670
  • Generator protection REG670

Other series have been the 650 (REC650 with control and backup protection; RET650 for transformers with integrated voltage controller and REL650 line distance protection) designed for high voltage grids.
The 630 series came out for medium voltage. Feeder protection was REF630 came with distance, overcurrent and earth fault protection as well as additional modules like frequency protection and synchro-check. The REM630 was the variant for motor protection. Transformer protection RET630 was developed for 2-winding-transformes and came with overcurrent, voltage and frequency protection as well as synchro-check.
Another vendor of IEDs is the Swiss NSE AG. Their KOMBISAVE devices are mainly developed for medium voltage protection and industry.

The SG-50, released in Germany in 2012 and distributed by SAE-IT is combining overcurrent with optional reclosing functionality. Transformer protection is included with thermal replica. Machine protection is included as well as the reactive power undervoltage protection (QU) mandatory in Germany for DER.
Busbar protection is possible as well as intermediate earth fault protection. Additional polygonal distance protection is available (Figure 8).

The numerical device KOMBISAVE+ with differential protection was released in 2015.  SIFANG’s (Figure 7) IED CSL103 (line differential) production started in 2000. SIFANG’s IEDs are used in Three Gorges Project (500 kV, put into operation in September 2000).
SIFANG CSC-103 (Figures 6a/b) is selective, reliable and high speed comprehensive transmission line protection IED for overhead lines, cables or combination of them. It is a solution for Overhead lines and cables up to 1000kV voltage level, two and three-end lines, all type of station arrangement, such as 1.5 breakers arrangement, double bus arrangement, etc. and extremely long lines as well as short lines.

As mentioned Intelligent Electronic Device, an IED, as it relates to the protection and power system automation industry, is a device that performs electrical protection functions, advanced local control intelligence, has the ability to monitor processes and can communicate directly to a SCADA system. It was used by different vendors for a long time already.

SEL produced the current differential and overcurrent protection SEL-387 since 1997. In 2002 high-impedance SEL-587Z was released. Busbar- and breaker failure SEL-487B as well as line differential SEL-311L have been presented in 2003. In 2004 the SEL-311L was the first line current differential relay with subcycle fault detection.  Since 2005 distance relay SEL-421 is available, the first subcycle transmission line distance protective relay with user programmable logic for protection and automation functions, synchronized phasor measurement integral to a protective relay, and adaptive ground directional element.  In 2006 SEL-710 - a motor protection relay with a thermal model that dynamically calculates slip to provide highly accurate temperature tracking, was presented. One year later (2007) the voltage controller SEL-2431 came with the 32 steps and single pole control (common in US).
SEL-451 - The first high-impedance fault detection for downed conductor detection in a feeder relay which also includes user programmable logic for protection and automation functions, synchronized phasor measurement, and multiple settings groups is available since 2007.

Production of transformer relay SEL-487E started in 2008, since 2009 the capacitor control and protection IED SEL-487V is there. The arc flash detection system with optical sensing, automated self-test, and over current supervision integral to a feeder relay- SEL-751A - could be presented in 2009.

The SEL-651R for recloser control with SEL-651R as the first high-impedance fault detection for downed conductor detection in a recloser control relay was presented in 2012, SEL-849 as integrated optical arc flash detection with overcurrent supervision and internal current sensing in a low voltage motor relay one year later. Also in 2013 SEL-411L with high accuracy traveling wave fault location as an integral function to a line protection relay that includes line differential and distance protection was presented.

The SEL-300G, the first microprocessor-based technology to comply with IEEE turbine protection standards, includes several unique features designed for protection, monitoring, and control of electrical generators. SEL designed the SEL-300G to meet the needs of a variety of users, including utility and industrial power plants and generator set manufacturers. In addition to comprehensive metering and reporting capabilities, the SEL-300G features include 100% stator ground fault protection, out-of-step protection, over excitation protection, directional power element protection, and RTD-based protection (Figure in PAC World December 2011) (Figures 9, 10). The SEL-700G with intertie and generator protection was released in 2010 (Figure 11).

Basler produced the BE1-24 Volts per Hertz Relay as microprocessor based to provide a new standard in versatility and control in protecting generators, transformers, and iron core reactors from the adverse effects of overexcitation since 1998. Later, in 2008 with BE1-951 another multifunctional system was available (Figure 12).

An overcurrent protection system was available with the BE1-1051 in 2009. In 2010 the Basler BE1-700V digital voltage/frequency protective relay has been added. (Figure 13). For the application of ground directional overcurrent protection the BE1-67N was made the same year (Figure 14).
For generator protection BE1-11g and m came out (Figure 15) in 2012.

Toshiba’s IED history started in 1999 with compact & high performance numerical relay (GR-series) and Substation automation system (GSC1000). In 2000 network solution equipment for the system monitoring and measurement was released. GPS synchronization for line differential (GRL 100) was installed in a 400-kV-network in UK in 2002. Distance relay with integrated communication GRZ100 could be presented in 2003, IEC 61850 was added in 2004 where a prototype was demonstrated at CIGRE in Paris. Fully numerical line differential protection for communication either by pilot wire or direct fiber optic link (GRL150) is available since 2005. The GRE came out in 2010 and GRL200 series was added in 2014. Figures 16 and 18 show the GRE110. CEE with their series Procom 7000 und Procom 700 should not be forgotten (1998).  Digital multicurve directional protection was RMSD 7000. The directional relay was RMSD 7900. (Figure 17).

ASHIDA is an important IED producer in India. Their railway protection ADR219 was released in 2002, numerical protection Aditya Series is available since 2003.
In 2009 motor, feeder and transformer protection was added (ADR244, ADR141 and ADR233), and digital protection ADR239A is produced since 2010.

Mitsubishi Electric Corporation has released product series for protective and control systems in the network age in 2001. The MELPRO-C series for power generation and distribution systems and the MELPRO-D series for user systems. Both series provide for interconnection using the networks inside power stations and the intranets and real-time networks of utility companies. They facilitate the remote operation of equipment, supporting remote maintenance, monitoring, and other new functions and services (block diagram in Figure 19).

Going back to AREVA/ALSTOM we want to talk about communication. For line differential communication SDH/SONET with MiCOM P594 was used- self healing and GPS-synchronized (1999, Figure 21).

With the experiences made since 1980 in PXLP, PXLN, EPAC3xxx (1995), Quadramho (1984), LFZP (1989) and Optimho (1989) 2001 the development of distance relay MiCOM P44x could be finished. Figure 22 shows the development of operating time, Figures 24 and 25 the functions inside.  AREVA’s P439 (Figure 20) combined several protection functions already.

After the division into ALSTOM Grid and Schneider Electric, Schneider presented the MiCOM Px30 series in 2013. With a new processor board new functions could be implemented, also IEC 61850 Ed. 2 will be available with these devices for the first time.

Also GE was and is very active in developing IEDs. Figure 23 shows a communication module from 1998.
The relay types presented at this time:

  • F30 feeder management (1998)
  • L90 line current differential (1998)
  • C30 controller and metering ((1999)
  • C60 controller, metering and breaker failure (1999)
  • F60 feeder management (1999)
  • T60 transformer management (1999)
  • D60 line distance (1999)
  • L60 line current phase comparison relay (1999)

To be continued.     

BeijingSifang June 2016