Capacitor Bank Protection & Control

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The MultilinTM C70 is an integrated protection, control, and monitoring device for shunt capacitor banks based on the well established and proven Multilin Universal Relay (UR) platform. The C70 provides both the bank and system protection schemes for shunt capacitor bank protection. The current and voltagebased protection functions are designed to provide sensitive protection for grounded, ungrounded single, and parallel capacitor banks and banks with taps, for a variety of capacitor bank configurations. The sophisticated built-in control functions can be used to automate capacitor switching with ease and flexibility for automatic voltage regulation of the system. In addition, the C70 comes with a variety of versatile features truly integrating protection, monitoring, metering, communication and control in one easy-to-use device.

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Key Benefits

• Comprehensive capacitor bank protection for a variety of configurations with sensitive current and voltage balance protection functions

• Adaptive compensation techniques truly compensate for the inherent bank unbalance, providing sensitive protection

•  Custom programmable logic for advanced shunt capacity bank controls

• Flexible automatic voltage regulation of shunt capacitor banks along with control supervision

• An integrated large, full color display, provides real-time visualization and control of the protected bay, via a bay mimic as well as annunciator functionality and graphical visualization of phasors

• Advanced IEC 61850 Ed. 1 and Ed. 2 certified implementation, complete settings via SCL files and IEC 61850-9-2 process bus solution ensures interoperability, device managing optimization and reduced cost of ownership

• Routable GOOSE (R-GOOSE) enables customer to send GOOSE messages beyond the substation, which enables WAPC and more cost effective communication architectures for wide area applications

• Increased network availability via failover time reduced to zero through IEC® 62439-3 “PRP” support

• Supports IEEE C37.111-1999/2013, IEC 60255-24 Ed 2.0 COMTRADE standard

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Applications

• Protection, control, monitoring and automation of shunt capacitor banks at different voltage levels

• Sensitive protection for grounded and ungrounded single and parallel capacitor banks and banks with taps, for a variety of capacitor bank configurations

• Suitable for protecting multiple capacitor banks

• Capacitor bank-based automatic voltage regulator (AVR) and capacitor control supervision

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Introduction
Part of the Multilin UR family of Protection & Control devices, the Multilin C70 Capacitor Bank Protection and Control System offers a high degree of modularity in its design and functionality, providing superior performance
while meeting the toughest requirements of the marketplace. Coupled with the unparalleled EnerVista software toolsets, common architecture and user-friendly interfaces helps managing the relay and the power system in the
easiest way. Advanced protection and control features of the Multilin C70 Capacitor Bank Protection and Control System includes:

Protection
C70 provides sensitive protection functions designed specifically to protect the shunt capacitor banks effectively. The C70 provides current-based protection functions, which include phase, ground, and neutral instantaneous and time overcurrent elements for standard overcurrent protection of the bank. Two elements per configured CT bank are available.

The standard current-based protection functions include:

• Phase instantaneous overcurrent (50P)

• Phase time overcurrent (51P)

• Phase directional (67P)

• Thermal overload (49)

• Ground instantaneous overcurrent (50G)

• Ground time overcurrent (51G)

• Neutral instantaneous overcurrent (50N)

• Neutral time overcurrent (51N)

• Neutral directional overcurrent with dual polarity criteria (67N)

• Negative sequence instantaneous overcurrent (50_2)

• Negative sequence time overcurrent (51_2)

• Negative sequence directional overcurrent (67_2)

 

The C70 also provides breaker failure protections and standard voltage-based protection functions which include:

• Phase overvoltage (59P)

• Phase undervoltage (27P)

• Auxiliary overvoltage (59X)

• Neutral overvoltage (59N)

• Negative sequence undervoltage (27N)

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Apart from the standard current and voltagebased functions, the C70 comes with protection functions specifically designed to provide sensitive protection for capacitor banks in a single box. Typical configurations with their associated model numbers are shown.

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Control
The C70 is provided with built-in control functions to help end users build capacitor bank control schemes of their choice with ease and flexibility.

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Advanced Automation
The C70 incorporates advanced automation features including powerful FlexLogic programmable logic, communication, and SCADA capabilities that far surpass what is found in the average capacitor bank relay. The C70 integrates seamlessly with other UR relays for complete system protection.

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IEC 61850 Process Bus
The IEC 61850 Process Bus module is designed to interface with the GE Multilin HardFiber System, allowing bi-directional IEC 61850 fiber optic communications. The HardFiber System is designed to integrate seamlessly with existing UR applications, including protection functions, FlexLogic, metering and communications.

The GE Multilin HardFiber System offers the following benefits:

• Communicates using open standard IEC 61850 messaging

• Drastically reduces P&C design, installation and testing labor by eliminating individual copper terminations

• Integrates with existing C70’s by replacing traditional CT/VT inputs with the IEC 61850 Process Bus module

• Does not introduce new cyber security concerns

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Monitoring and Metering
The C70 includes high accuracy metering and recording for all AC signals. Voltage, current, and power metering are built into the relay as a standard feature. Current and voltage parameters are available as total RMS
magnitude, and as fundamental frequency magnitude and angle.

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