Product Description; Introduction; Overview - GE C70 Instruction Manual

2 PRODUCT DESCRIPTION

2.1 INTRODUCTION

2 PRODUCT DESCRIPTION 2.1INTRODUCTION

2.1.1 OVERVIEW

The C70 Capacitor Bank Protection and Control System is a UR-series microprocessor-based relay for protection and con-
trol of small, medium, and large three-phase capacitor banks. The relay can be ordered with up to three CT/VT modules,
allowing for flexible application to variety of bank configurations.
The key protection functions are designed to cover grounded and ungrounded, single and parallel banks. Sensitive protec-
tion functions support compensation for both external (system) unbalance and inherent unbalance of the capacitor bank
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itself. Both voltage and current-based balance protection functions are available. Algorithms are developed to automatically
select compensation settings after repairs or other alternations of the bank.
The relay supports variety of bank configurations through flexible configurations of its AC inputs, installed voltage and cur-
rent transformers, and resulting protection techniques.
The relay incorporates an automatic voltage regulator (AVR) responding to either voltage, reactive power, or power factor.
A separate timer function initiates controls on a pre-defined time/date basis. These on-off type controls are meant to auto-
matically close or open the associated breaker. A supervisory function is provided to program the local/remote, auto/man-
ual functionality, temporary inhibit closing after tripping, and other auxiliary functions such as operation counters.
A capacitor control element provides remote/local and auto/manual control regulation, trip/close interlocking, and seal-in. A
user-programmable time delay inhibits closing until after the bank discharges itself to a safe level.
Up to six contact input/output modules can be ordered. The relay can also equipped with a serial 64/128 kbps direct input/
output module for fast and reliable peer-to-peer communication with other UR-series IEDs.
The C70 metering functions include true RMS and phasors for currents and voltages, current and voltage harmonics and
THD, symmetrical components, frequency, power, power factor.
Diagnostic features include an event recorder capable of storing 1024 time-tagged events, oscillography capable of storing
up to 64 records with programmable trigger, content and sampling rate, and data logger acquisition of up to 16 channels,
with programmable content and sampling rate. The internal clock used for time-tagging can be synchronized with an IRIG-
B signal or via the SNTP protocol over the Ethernet port. This precise time stamping allows the sequence of events to be
determined throughout the system. Events can also be programmed (via FlexLogic™) to trigger oscillography data capture
which may be set to record the measured parameters before and after the event for viewing on a personal computer. These
tools significantly reduce troubleshooting time and simplify report generation in the event of a system fault.
Several options are available for communication. A faceplate RS232 port can be used to connect to a computer for the pro-
gramming of settings and the monitoring of actual values. The RS232 port has a fixed baud rate of 19.2 kbps. The rear
RS485 port allows independent access by operating and engineering staff. It can be connected to system computers with
baud rates up to 115.2 kbps. All serial ports use the Modbus RTU protocol. The 100Base-FX Ethernet interface provides
fast, reliable communications in noisy environments. The Ethernet port supports IEC 61850, Modbus/TCP, and TFTP proto-
cols, PTP (according to IEEE Std. 1588-2008 or IEC 61588), and allows access to the relay via any standard web browser
(C70 web pages). The IEC 60870-5-104 protocol is supported on the Ethernet port, and DNP 3.0 and IEC 60870-5-104
cannot be enabled at the same time. The Ethernet port also supports the Parallel Redundancy Protocol (PRP) of IEC
62439-3 (clause 4, 2012) when purchased as a CPU module option.
The C70 IEDs use flash memory technology which allows field upgrading as new features are added. The following single
line diagram illustrates the relay functionality using ANSI (American National Standards Institute) device numbers.
GE Multilin C70 Capacitor Bank Protection and Control System 2-1