GE B30 Instruction Manual

Also see for b30: Maintenance manual Instruction manual Instruction manual Instruction manual Communications manual

Contents

CHAPTER 5: SETTINGS OVERVIEWB30 BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 5-55Many settings are common to most elements, outlined as follows:• FUNCTION setting — This setting programs the element to operate when selected as “Enabled.” The factory default is“Disabled.” Once “Enabled,” any element associated with the function becomes active and all options becomeavailable.• NAME setting — This setting is used to uniquely identify the element.• SOURCE setting — This setting is used to select the AC source to be monitored. See the Introduction to AC Sourcessection later.• PICKUP setting — For simple elements, this setting is used to program the level of the measured parameter above orbelow which the pickup state is established. In more complex elements, a set of settings can be provided to define therange of the measured parameters that cause the element to pick up.• PICKUP DELAY setting — This setting sets a time-delay-on-pickup, or on-delay, for the duration between the pickupand operate output states.• RESET DELAY setting — This setting is used to set a time-delay-on-dropout, or off-delay, for the duration between theoperate output state and the return to logic 0 after the input transits outside the defined pickup range.• BLOCK setting — The default output operand state of all comparators is a logic 0 or “flag not set.” The comparatorremains in this default state until a logic 1 is asserted at the RUN input, allowing the test to be performed. If the RUNinput changes to logic 0 at any time, the comparator returns to the default state. The RUN input is used to supervisethe comparator. The BLOCK input is used as one of the inputs to RUN control.• TARGET setting — This setting is used to define the operation of an element target message. When set to "Disabled,"no target message or illumination of a front panel LED indicator is issued upon operation of the element. When set to“Self-Reset,” the target message and LED indication follow the operate state of the element and self-resets once theoperate element condition clears. When set to “Latched,” the target message and LED indication remains visible afterthe element output returns to logic 0 until a RESET command is received by the relay.• EVENTS setting — This setting is used to control whether the pickup, dropout, or operate states are recorded by theevent recorder. When set to “Disabled,” element pickup, dropout, or operate are not recorded as events. When set to“Enabled,” events are created for PKP (pickup) DPO (dropout) OP (operate)The DPO event is created when the measure and decide comparator output transits from the pickup state (logic 1) tothe dropout state (logic 0). This can happen when the element is in the operate state if the reset delay time is not zero.Not every operand of a given element in a UR relay generates events, only the major output operands. Elements,asserting output per phase, log operating phase output only, without asserting the common three-phase operandevent.5.2.2 Introduction to AC sources5.2.2.1 BackgroundA mechanism called a source configures the routing of CT and VT input channels to measurement sub-systems. Sources, inthe context of UR series relays, refer to the logical grouping of current and voltage signals such that one source contains allthe signals required to measure the load or fault in a particular power apparatus. A given source can contain all or some ofthe following signals: three-phase currents, single-phase ground current, three-phase voltages, and an auxiliary voltagefrom a single VT for checking for synchronism.The basic idea of an AC source is to select a point on the power system where the voltages and currents are of interest. Toillustrate the concept of sources, as applied to current inputs only, consider the breaker-and-a-half scheme that follows.(The breaker-and-a-half scheme is used for illustrative purposes and is available on select UR products.) In this application,the current flows as shown by the arrows. Some current flows through the upper bus bar to some other location or powerequipment, and some current flows into transformer winding 1. The current into winding 1 is the phasor sum (or difference)of the currents in CT1 and CT2 (whether the sum or difference is used depends on the relative polarity of the CTconnections). The same considerations apply to transformer winding 2. The protection elements require access to the netcurrent for transformer protection, but some elements can need access to the individual currents from CT1 and CT2.