Paralleling device

Paralleling device – SIPROTEC 7VE85


Paralleling device SIPROTEC 7VE85 is specifically designed for the synchronization of generators (power plant units) with the power grid or synchronization of 2 electricity-supply systems. The 1.5- and 2-channel synchronization function is the made function of the SIPROTEC 7VE85. To warrant a high level of security and reliability, the software works with various monitoring functions. In addition, the most important hardware components are duplicated. Two different measuring algorithms are used in accordance with the multi-channel redundancy. This avoids overfunctions through systematic errors. At the same time, the different methods of measurement are applied and processed independently of each other with different memory areas. The high level of reliability and flexible options to adapt to the equipment requirements allow a wide variety of applications.

Features & functions

Paralleling device SIPROTEC 7VE85


Main function

  • 1.5- and 2-channel synchronization function

Inputs and outputs

2 predefined standard variants with up

  • to 8 current transformers,
  • 8 voltage transformers, 
  • 7 to 15 binary inputs,
  • 14 to 20 binary outputs

Hardware flexibility

  • Flexibly adjustable and expandable I/O quantity structure within the scope of the modular SIPROTEC 5 system; 1/6 expansion modules can be added, available with large or small display, or without display

Width of housing

  • 1/3 × 19 inches to 2 × 19 inches

As standard:


The SIPROTEC 7VE85 recognizes the operating conditions automatically and reacts in accordance with the settings. In
“Switching synchronous electrical power systems” operating mode the frequency difference is measured with a high level of accuracy. If the frequency difference is almost zero for a long time, this is referred to as a synchronous electrical power
system, for which a wider switching angle can be permitted.


If asynchronous conditions occur, such as when synchronizing the generators, the speed is automatically adjusted to the power frequency and the generator voltage in an electrical power system. It is then switched, taking into consideration the synchronization in accordance with the circuit breaker closing time.


The 1.5-channel parallel switching function (synchronization function and synchrocheck) is provided for use in small to

medium-sized generators and in electrical power systems. This function is more secure than a 1-channel paralleling device and can also be used for synchrocheck applications. For larger Generators and electrical power systems with high safety requirements, the 2-channels parallel switching function is recommended.


In this example two distinctly independent methods of measurement decide on the switching conditions.

Furthermore, SIPROTEC 7VE85 offers additional current, frequency, power and voltage protection functions and many
other control and monitoring functions. As a result, the paralleling device offers synchronization and protection functions in a single device. With its modular structure, flexibility and the powerful DIGSI 5 engineering tool, the SIPROTEC 7VE85 device offers future-oriented system solutions with high investment security and low operating costs.


The following modes of operation are covered:


  • Switching synchronous/asynchronous electrical power systems
  • Switching to de-energized line or dead busbar
  • Synchrocheck function
  • Adjusting commands for voltage and frequency (speed)



DIGSI 5 permits all functions to be configured and combined as required.

  • Stabilization function for the output of adaptive frequency control pulses

  • Synchrocheck function for manual synchronization

  • Analog output of operational measured values*

  • Commissioning (measurement of the operating time of the circuit breaker, sample synchronization)

  • Functionality for protection and network decoupling tasks

  • Undervoltage protection (ANSI 27)

  • Overvoltage protection (ANSI 59)

  • Voltage differential protection (ANSI 60)

  • Overcurrent Protection (ANSI 50/51)

  • Vector Jump

  • Overfrequency (ANSI 81)

  • Underfrequency (ANSI 81)

  • Rate-of-frequency-change protection (ANSI 81R)

  • Instantaneous high-current tripping (ANSI 50HS)

  • Instantaneous tripping at switch upon error

  • Power protection active/reactive power (ANSI 32/37)

  • Power-plant disconnection (ANSI 37)

  • Circuit-Breaker Failure Protection (ANSI 50BF)

  • Circuit breaker reignition monitoring (RBRF)

  • Extensive cyber security functionality, such as role-based access control (RBAC), protocolling security-related events or signed firmware

  • Simple, quick and secure access to device data via a standard Web browser – without additional software


    *in preparation


  • Synchronization of generators (power plant units) with the electricity-supply system under consideration of the vector group of transformers and transformer tap*
  • Synchronization of 2 electricity-supply systems

  • Operation of up to 8 synchronizing points without external switchover

* being prepared


  • Safe and reliable synchronization of generators and electricity-supply systems by multichannel redundancy
  • Purposeful and easy handling of devices and software thanks to a user-friendly design

  • Cost savings as no external switchover of synchronization and voltage measuring points is required

  • Cyber security in accordance with NERC CIP and BDEW Whitepaper requirements
  • Highest availability even under extreme environmental conditions by “conformal coating“ (coating) of the modular assemblies (being prepared)
  • Powerful communication components warrant safe and effective solutions
  • High investment security and low operating costs due to future-oriented system solutions