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| In a Power System, substation is an assembly of technology and facility that carry out major functions
such as distribution of power, up-down transform voltage and protection and control of system. |
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| Within system, a busbar offers as an important function of which power gets concentrated and
distributed through transmission lines. Thus in a busbar, an effect of fault goes on whole substation,
which can lead into a severe black out accident by large fault current. In order to prevent this, multiple
circuit breaker and switch gear are composed as parts of double busbar protection. |
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| With the importance of busbar, in a double busbar structure,
protection system is divided into Bus 1 and Bus 2 protection
zone. Each of them protects system separately so as to save
outage time when there is maintenance and accident. Also
through incoming and outgoing current of whole busbar, Check
Zone protection function checks internal fault. |
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| Main protection used in busbar protection includes
current differential relay (87T). And backup protection
includes under voltage protection relay using primary and
secondary side’s voltage transformer (VT) input source. |
| GABO’s busbar protection panel has main protection
relay including Central Unit (7SS522) combined with Bay
Unit (7SS525) made from SIEMENS. By having
accumulated knowledge in manufacturer technology of
protection panel, and with experienced professionals, we
strive to accomplish noise immunity, stable earthing,
durability, insulation, assembly, all of which being
incorporated in order to generate credible products. |
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BUSBAR PROTECTION SYSTEM CONFIGURATION |
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| Busbar protection system is organized into Central Unit
and Bay Unit. A Bay Unit measures current and control
switchgear of each bay. And Central Unit checks internal
fault of busbar by obtaining information from each Bay
Unit. |
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CENTRAL UNIT & BAY UNIT (7SS5x) |
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| - Digital Protection Relay with 32 Bit high-speed microprocessor. |
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| - Substation system configuration in graphics by using DIGSI software. |
| - Supports up to 12 Bus zones, and up to 12 Bus couplers. |
| - Selectable up to 48 Bus Units, and many Bus bar Protection. |
| - Independent and separate setting of Bus Zone and Check Zone. |
| - Accurate detection on internal/external fault by using a differential current protection. |
| - Offers selectable protection zone (Bus zone, Check zone) of multiple busbar system. |
| - Control and measurement of each Bay unit in Central unit. |
| - Enhancement of stability and speed of a system through fiber-optic connection. |
| - Stable activation through ratio current differential characteristics. |
| - Auto-compensation functions on current transformer ratio mismatch. |
| - Convenient function such as Remote setting/ Fault analysis by software. |
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DIFFERENTIAL CURRENT PROTECTION CHARACTERISTICS CURVE |
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| Depending on a ratio between restraint current and differential
current, it is divided into trip zone and non-trip zone. A restraint
current has a stable restraint property that which compensates a
current transformer error and CT saturation. |
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CENTRAL UNIT & BAY UNIT (7SS5x) MAIN FUNCTIONS |
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| - Current differential protection (independent protection function on each phase) |
- User defined logic (CFC-continuous function chart). |
| - Breaker Failure protection |
- Function to prevent mal-function through many fault detection. |
| - Prevention of mal-operation by using CT saturation detection |
- Self-diagnosis |
| - Current transformer ratio mismatches compensation through setting |
- Selection possible to one pole/three pole trip function |
| - Circuit breaker status check function through low current detection |
- Metering (current, voltage, active/ reactive power, etc) |
| - End fault protection between current transformer and circuit breaker |
- Event recording function (trip, alarm, fail, etc) |
| - High speed tripping function |
- Using any portable computing device, setting and fault analysis
function (analysis program (DIGSI), Comrade File conversion
function) becomes possible. |
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CU & BU (7SS5X) TECHNICAL SPECIFICATION/STANDARD |
| Index |
Item |
Central Unit |
Bay Unit |
| Rating |
Power Supply |
Voltage Input |
DC : 48/60, 110/125, 220/250 [V] |
| Power Consumption |
35[W] ~ 135[VA] |
16[W] |
| Analog |
Current |
1[A], Burden : 0.1[VA]
5[A], Burden : 0.2[VA] |
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| Digital input |
Number of digital input : 12
Voltage Range : 88 ~ 300[VDC] |
20(10)
88 ~ 300[VDC] |
| Digital Output |
Number of digital output : 16+1
Allowable Current : Continus(5[A]), 30[A](0.5[sec]) |
5+1+1
Continus(5[A]), 30[A](0.5[sec]) |
| Communication |
Communication Port |
RS-232, RS-485, Ethernet, FO(Fiber Optic) |
RS-232, FO(Fiber Optic) |
| Protocol |
Profibus, DNP3.0, IEC61850, IEC60870, TCP/IP |
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| Time Synchronization |
DCF77/IRIG-B/SNTP |
Selectable |
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