Description

MIW Directional Power / Loss of Field

The GE MIW Directional Power, part of the M Family, is a digital relay that provides directional power and loss of field protection for generators of any size. The MIW provides metering values for Ia, voltage values, P, Q, S, V1, V2 and angle. A 24 event record and oscillography data help with troubleshooting and performance analysis.

Applications
• Controlling power flow in alternating current generator applications of any size
• enerVista.com compatible

GE MIW Directional Power – Protection and Control
• Reverse power (32RP)
• Forward overpower
• Low forward power (32LF)
• Loss of field/excitation (40)
• Fuse failure (60)

Monitoring and Metering
• Power metering

User Interface
• M+ Setup software for setting and monitoring
• RS232 port, faceplate accessible (19.2 kbps, ModBus RTU)
• RS485 rear port (19.2 kbps, ModBus RTU)

Features and Benefits
■ Advanced 16-bit microprocessor
■ Loss of field unit to detect loss of excitation
■ Configurable logic, curves, digital I/Os and LEDs
■ Flash memory for field upgrades
■ Two settings groups
■ Drawout case for serviceability

Applications

Controlling power flow in alternating current generator applications of any size

Protection and Control Of GE MIW Directional Power

• Reverse, forward overpower, low forward power
• Loss of field/excitation, fuse failure Monitoring and Metering
• Power metering

User Interfaces

• M+PC software for setting and monitoring
• RS232 and RS485 ports for local and remote access

Protection

The MIW, part of the M Family, is a digital relay that provides directional power and loss of field protection for generators of any size. Advanced protection functions include:

Directional Reverse Power

If three-phase total power exceeds the pickup level in the reverse direction (negative MW) for a period of time, a trip will occur. The pickup level is set by per unit of generator MW calculated from rated MVA and power factor.
If the generator accelerates via the power system rather than the prime mover, the reverse power element may be blocked for a chosen time period.

Directional Low Forward Power

If the three-phase total power in the forward direction (positive MW) falls below the pickup level for a chosen period of time, an alarm will occur. The pickup level is programmed as above in directional reverse power.
The low forward power element is active only when the generator is online. The pickup level should be set lower than expected generator loading during normal operations.

Loss of Excitation

Loss of excitation is detected via an impedance element. If the impedance falls within the impedance circle for the delay time specified, a trip will occur.

The user can enable circle #1 and/or circle #2 to tune the protection feature to their system. The larger circle diameter can be set to the synchronous reactance of the generator xd, and the circle offset should be set to the generator transient reactance x’d/2. This element will be blocked if there is a fuse failure condition or if the generator
is offline.

Fuse Failure
The MIW includes a VT fuse failure unit which measures the value of negative sequence voltage against positive sequence voltage and the current value.

Inputs and Outputs
The factory configuration of MIW inputs and outputs can be easily modified using M+PC software.
Two digital inputs and six relay outputs are provided, four of them programmable. These configurable outputs can be assigned either to a set of pre-configured values, or to an OR/NOT combination of the same values.

We offer GE’s century long tradition of power system innovation. From generators to transmission lines, to motors and beyond, we ensure dependable, safe power worldwide. GE offers a wide range of single function and auxiliary relays, along with a portfolio of accessories, to support high performing and reliable protection and control systems. To explore the GE portfolio with us click here GE numerical Relays !